diff --git a/src/components/AppNavigation/CalendarList.vue b/src/components/AppNavigation/CalendarList.vue
index d88311a78e..9f1634778c 100644
--- a/src/components/AppNavigation/CalendarList.vue
+++ b/src/components/AppNavigation/CalendarList.vue
@@ -77,6 +77,14 @@
 				:calendar="calendar" />
 		</template>
 
+		<NcAppNavigationCaption v-if="sortedCalendars.delegated.length" :name="$t('calendar', 'Delegated')" />
+		<template v-if="!isPublic && sortedCalendars.delegated.length">
+			<CalendarListItem
+				v-for="calendar in sortedCalendars.delegated"
+				:key="calendar.id"
+				:calendar="calendar" />
+		</template>
+
 		<NcAppNavigationSpacer />
 
 		<!-- The header slot must be placed here, otherwise vuedraggable adds undefined as item to the array -->
@@ -98,6 +106,7 @@ import CalendarListItemLoadingPlaceholder from './CalendarList/CalendarListItemL
 import CalendarListNew from './CalendarList/CalendarListNew.vue'
 import PublicCalendarListItem from './CalendarList/PublicCalendarListItem.vue'
 import useCalendarsStore from '../../store/calendars.js'
+import useDelegationStore from '../../store/delegation.js'
 
 const limit = pLimit(1)
 
@@ -129,12 +138,13 @@ export default {
 		return {
 			calendars: [],
 			/**
-			 * Calendars sorted by personal, shared, and deck
+			 * Calendars sorted by personal, shared, deck, and delegated
 			 */
 			sortedCalendars: {
 				personal: [],
 				shared: [],
 				deck: [],
+				delegated: [],
 			},
 
 			disableDragging: false,
@@ -143,7 +153,7 @@ export default {
 	},
 
 	computed: {
-		...mapStores(useCalendarsStore),
+		...mapStores(useCalendarsStore, useDelegationStore),
 		...mapState(useCalendarsStore, {
 			serverCalendars: 'sortedCalendarsSubscriptions',
 		}),
@@ -182,9 +192,15 @@ export default {
 				personal: [],
 				shared: [],
 				deck: [],
+				delegated: [],
 			}
 
 			this.calendars.forEach((calendar) => {
+				if (calendar.isDelegated) {
+					this.sortedCalendars.delegated.push(calendar)
+					return
+				}
+
 				if (calendar.isSharedWithMe) {
 					this.sortedCalendars.shared.push(calendar)
 					return
diff --git a/src/components/AppNavigation/CalendarList/CalendarListItem.vue b/src/components/AppNavigation/CalendarList/CalendarListItem.vue
index b8cc504872..7f889436c3 100644
--- a/src/components/AppNavigation/CalendarList/CalendarListItem.vue
+++ b/src/components/AppNavigation/CalendarList/CalendarListItem.vue
@@ -26,16 +26,36 @@
 
 		<template #counter>
 			<LinkVariant v-if="isSharedByMe" :size="20" />
+			<NcAvatar
+				v-else-if="isDelegated && loadedOwnerPrincipal && !actionsMenuOpen"
+				:user="ownerUserId"
+				:displayName="ownerDisplayname"
+				:title="ownerDisplayname"
+				:hideStatus="true"
+				:size="20"
+				class="delegated-counter-avatar" />
 			<NcAvatar
 				v-else-if="isSharedWithMe && loadedOwnerPrincipal && !actionsMenuOpen"
 				:user="ownerUserId"
 				:displayName="ownerDisplayname" />
-			<div v-else-if="isSharedWithMe && !loadedOwnerPrincipal" class="icon icon-loading" />
+			<div v-else-if="(isSharedWithMe || isDelegated) && !loadedOwnerPrincipal" class="icon icon-loading" />
 		</template>
 
 		<template #actions>
 			<template v-if="!isBeingDeleted">
-				<template v-if="isSharedWithMe">
+				<template v-if="isDelegated">
+					<NcActionCaption :name="$t('calendar', 'Delegated to you by')" />
+					<NcActionText class="delegated-action-text">
+						<template #icon>
+							<div class="actions-icon-avatar">
+								<NcAvatar :user="ownerUserId" :displayName="ownerDisplayname" :size="30" />
+							</div>
+						</template>
+						{{ ownerDisplayname }}
+					</NcActionText>
+					<NcActionSeparator />
+				</template>
+				<template v-else-if="isSharedWithMe">
 					<NcActionCaption :name="$t('calendar', 'Shared with you by')" />
 					<NcActionText>
 						<template #icon>
@@ -143,7 +163,7 @@ export default {
 		canBeShared() {
 			// The backend falsely reports incoming editable shares as being shareable
 			// Ref https://github.com/nextcloud/calendar/issues/5755
-			if (this.calendar.isSharedWithMe) {
+			if (this.calendar.isSharedWithMe || this.calendar.isDelegated) {
 				return false
 			}
 
@@ -165,7 +185,16 @@ export default {
 		 * @return {boolean}
 		 */
 		isSharedWithMe() {
-			return this.calendar.isSharedWithMe
+			return this.calendar.isSharedWithMe && !this.calendar.isDelegated
+		},
+
+		/**
+		 * Is the calendar delegated to me by another user?
+		 *
+		 * @return {boolean}
+		 */
+		isDelegated() {
+			return !!this.calendar.isDelegated
 		},
 
 		/**
@@ -272,6 +301,7 @@ export default {
 		 * Open the calendar modal for this calendar item.
 		 */
 		showEditModal() {
+			console.log('getting here')
 			this.calendarsStore.editCalendarModal = { calendarId: this.calendar.id }
 		},
 
@@ -308,6 +338,16 @@ export default {
 		height: 44px;
 	}
 
+	// Size and position the delegated avatar in the counter slot to match icon buttons
+	.delegated-counter-avatar {
+		margin-inline-start: auto;
+	}
+
+	// Vertically align the owner name with the avatar in the "Delegated to you by" row
+	:deep(.action-text__text) {
+		align-self: center ;
+	}
+
 	// Hide avatars if list item is hovered
 	:deep(.app-navigation-entry:hover .app-navigation-entry__counter-wrapper) {
 		display: none;
diff --git a/src/components/AppNavigation/Settings.vue b/src/components/AppNavigation/Settings.vue
index 7aef49bc80..32754403de 100644
--- a/src/components/AppNavigation/Settings.vue
+++ b/src/components/AppNavigation/Settings.vue
@@ -126,6 +126,11 @@
 						<SettingsAttachmentsFolder />
 					</NcFormGroup>
 				</NcAppSettingsSection>
+				<NcAppSettingsSection
+					id="settings-modal-delegation"
+					:name="t('calendar', 'Delegation')">
+					<SettingsDelegationSection />
+				</NcAppSettingsSection>
 				<EventLegend />
 				<ShortcutOverview />
 			</NcAppSettingsDialog>
@@ -158,6 +163,7 @@ import CogIcon from 'vue-material-design-icons/CogOutline.vue'
 import CalendarPicker from '../Shared/CalendarPicker.vue'
 import EventLegend from './Settings/EventLegend.vue'
 import SettingsAttachmentsFolder from './Settings/SettingsAttachmentsFolder.vue'
+import SettingsDelegationSection from './Settings/SettingsDelegationSection.vue'
 import SettingsImportSection from './Settings/SettingsImportSection.vue'
 import SettingsTimezoneSelect from './Settings/SettingsTimezoneSelect.vue'
 import ShortcutOverview from './Settings/ShortcutOverview.vue'
@@ -185,6 +191,7 @@ export default {
 		SettingsImportSection,
 		SettingsTimezoneSelect,
 		SettingsAttachmentsFolder,
+		SettingsDelegationSection,
 		ShortcutOverview,
 		CogIcon,
 		NcFormBox,
diff --git a/src/components/AppNavigation/Settings/SettingsDelegationSection.vue b/src/components/AppNavigation/Settings/SettingsDelegationSection.vue
new file mode 100644
index 0000000000..fcad3267b5
--- /dev/null
+++ b/src/components/AppNavigation/Settings/SettingsDelegationSection.vue
@@ -0,0 +1,459 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<template>
+	<div class="delegation-settings">
+		<NcNoteCard v-if="loadError" type="error">
+			{{ t('calendar', 'Could not load delegates.') }}
+		</NcNoteCard>
+
+		<NcFormGroup
+			:label="t('calendar', 'Delegates')"
+			:description="t('calendar', 'Allow users to manage your calendar events and invitations on your behalf.')">
+			<NcEmptyContent
+				v-if="loading"
+				icon="icon-loading"
+				class="delegation-settings__loading"
+				:description="t('calendar', 'Loading delegates\u2026')" />
+			<ul v-else class="delegation-settings__list">
+				<NcListItem
+					v-for="delegate in delegationStore.delegates"
+					:key="delegate.url"
+					:name="delegate.displayname || delegate.principalId"
+					:compact="true">
+					<template #subname>
+						{{ delegateSubname(delegate) }}
+					</template>
+					<template #actions>
+						<NcActionButton
+							:aria-label="t('calendar', 'Revoke access')"
+							@click="onRevokeClick(delegate)">
+							<template #icon>
+								<CloseIcon :size="20" />
+							</template>
+							{{ t('calendar', 'Revoke access') }}
+						</NcActionButton>
+					</template>
+				</NcListItem>
+			</ul>
+
+			<p v-if="!loading && delegationStore.delegates.length === 0" class="delegation-settings__empty">
+				{{ t('calendar', 'No delegates yet.') }}
+			</p>
+
+			<NcButton
+				class="delegation-settings__add-button"
+				variant="secondary"
+				:wide="true"
+				@click="openAddDelegate">
+				<template #icon>
+					<PlusIcon :size="20" />
+				</template>
+				{{ t('calendar', 'Add delegate') }}
+			</NcButton>
+		</NcFormGroup>
+
+		<!-- Revoke Confirmation Dialog -->
+		<NcDialog
+			v-if="revokeTarget"
+			:open="!!revokeTarget"
+			:name="t('calendar', 'Revoke access?')"
+			:message="revokeMessage"
+			:buttons="revokeButtons"
+			@update:open="onRevokeDialogClose" />
+
+		<!-- Add Delegate Dialog -->
+		<NcDialog
+			v-if="showAddDelegate"
+			:open="showAddDelegate"
+			:name="t('calendar', 'Add delegate')"
+			@update:open="onAddDelegateDialogClose">
+			<div class="delegation-add">
+				<NcSelect
+					v-model="selectedUser"
+					class="delegation-add__select"
+					:options="searchResults"
+					:searchable="true"
+					:internalSearch="false"
+					:loading="searchLoading"
+					:max-height="300"
+					:placeholder="t('calendar', 'Search for a user\u2026')"
+					:clearable="true"
+					:filterBy="filterSearchResults"
+					openDirection="below"
+					trackBy="url"
+					label="displayname"
+					@search="onSearch">
+					<template #no-options>
+						<span>{{ t('calendar', 'No users found') }}</span>
+					</template>
+					<template #option="user">
+						<div class="delegation-add__option">
+							<NcAvatar :user="user.principalId" :displayName="user.displayname" />
+							<div class="delegation-add__option-label">
+								<span>{{ user.displayname }}</span>
+								<span class="delegation-add__option-email">{{ user.emailAddress }}</span>
+							</div>
+						</div>
+					</template>
+				</NcSelect>
+				<p class="delegation-add__description">
+					{{ t('calendar', 'Choose whether they can view and edit events, or only view them.') }}
+				</p>
+			</div>
+			<template #actions>
+				<NcButton variant="secondary" @click="showAddDelegate = false">
+					{{ t('calendar', 'Cancel') }}
+				</NcButton>
+				<NcButton
+					variant="secondary"
+					:disabled="!selectedUser || addLoading"
+					@click="confirmAddDelegate('read')">
+					{{ t('calendar', 'Add as viewer') }}
+				</NcButton>
+				<NcButton
+					variant="primary"
+					:disabled="!selectedUser || addLoading"
+					@click="confirmAddDelegate('write')">
+					{{ t('calendar', 'Add as editor') }}
+				</NcButton>
+			</template>
+		</NcDialog>
+	</div>
+</template>
+
+<script>
+import { showError, showSuccess } from '@nextcloud/dialogs'
+import {
+	NcActionButton,
+	NcAvatar,
+	NcButton,
+	NcDialog,
+	NcEmptyContent,
+	NcFormGroup,
+	NcListItem,
+	NcNoteCard,
+	NcSelect,
+} from '@nextcloud/vue'
+import debounce from 'debounce'
+import { mapStores } from 'pinia'
+import CloseIcon from 'vue-material-design-icons/Close.vue'
+import PlusIcon from 'vue-material-design-icons/Plus.vue'
+import { principalPropertySearchByDisplaynameOrEmail } from '../../../services/caldavService.js'
+import useDelegationStore from '../../../store/delegation.js'
+import usePrincipalsStore from '../../../store/principals.js'
+import logger from '../../../utils/logger.js'
+
+export default {
+	name: 'SettingsDelegationSection',
+
+	components: {
+		NcActionButton,
+		NcAvatar,
+		NcButton,
+		NcDialog,
+		NcEmptyContent,
+		NcFormGroup,
+		NcListItem,
+		NcNoteCard,
+		NcSelect,
+		CloseIcon,
+		PlusIcon,
+	},
+
+	data() {
+		return {
+			/** Whether the data is being loaded */
+			loading: false,
+			/** Whether there was an error loading delegates */
+			loadError: false,
+			/** The delegate object pending revocation, or null */
+			revokeTarget: null,
+			/** Whether the add-delegate dialog is open */
+			showAddDelegate: false,
+			/** Currently selected user in the add-delegate dialog */
+			selectedUser: null,
+			/** Search results for user lookup */
+			searchResults: [],
+			/** Whether user search is in progress */
+			searchLoading: false,
+			/** Whether an add-delegate operation is in progress */
+			addLoading: false,
+		}
+	},
+
+	computed: {
+		...mapStores(useDelegationStore, usePrincipalsStore),
+
+		/**
+		 * Confirmation message for the revoke dialog.
+		 *
+		 * @return {string}
+		 */
+		revokeMessage() {
+			if (!this.revokeTarget) {
+				return ''
+			}
+			const email = this.revokeTarget.emailAddress
+				|| this.revokeTarget.displayname
+				|| this.revokeTarget.principalId
+			return this.t('calendar', '{email} will no longer be able to act on your behalf.', { email })
+		},
+
+		/**
+		 * Buttons for the revoke confirmation dialog.
+		 *
+		 * @return {object[]}
+		 */
+		revokeButtons() {
+			return [
+				{
+					label: this.t('calendar', 'Cancel'),
+					callback: () => { this.revokeTarget = null },
+				},
+				{
+					label: this.t('calendar', 'Revoke'),
+					type: 'error',
+					callback: this.confirmRevoke,
+				},
+			]
+		},
+
+	},
+
+	async created() {
+		this.loadError = false
+		this.loading = true
+		try {
+			await this.delegationStore.fetchDelegates()
+		} catch (error) {
+			logger.error('Failed to load delegates', { error })
+			this.loadError = true
+		} finally {
+			this.loading = false
+		}
+	},
+
+	methods: {
+		/**
+		 * Returns a descriptive subname for a delegate list item
+		 * showing their permission level and optionally their email.
+		 *
+		 * @param {object} delegate The delegate principal object
+		 * @return {string}
+		 */
+		delegateSubname(delegate) {
+			const permissionLabel = delegate.permission === 'read'
+				? this.t('calendar', 'Viewer')
+				: this.t('calendar', 'Editor')
+			if (delegate.emailAddress) {
+				return `${permissionLabel} · ${delegate.emailAddress}`
+			}
+			return permissionLabel
+		},
+
+		/**
+		 * Open the revoke confirmation dialog for a specific delegate.
+		 *
+		 * @param {object} delegate The delegate principal object
+		 */
+		onRevokeClick(delegate) {
+			this.revokeTarget = delegate
+		},
+
+		/**
+		 * Handle the revoke dialog close event.
+		 *
+		 * @param {boolean} open New open state
+		 */
+		onRevokeDialogClose(open) {
+			if (!open) {
+				this.revokeTarget = null
+			}
+		},
+
+		/**
+		 * Execute the revoke operation after user confirmation.
+		 */
+		async confirmRevoke() {
+			if (!this.revokeTarget) {
+				return
+			}
+			const delegate = this.revokeTarget
+			this.revokeTarget = null
+			try {
+				await this.delegationStore.removeDelegate({ principalUrl: delegate.url })
+				showSuccess(this.t('calendar', 'Access revoked successfully.'))
+			} catch (error) {
+				logger.error('Failed to revoke delegate access', { error })
+				showError(this.t('calendar', 'Could not revoke access.'))
+			}
+		},
+
+		/**
+		 * Open the add-delegate dialog.
+		 */
+		openAddDelegate() {
+			this.selectedUser = null
+			this.searchResults = []
+			this.showAddDelegate = true
+		},
+
+		/**
+		 * Handle the add-delegate dialog close event.
+		 *
+		 * @param {boolean} open New open state
+		 */
+		onAddDelegateDialogClose(open) {
+			if (!open) {
+				this.showAddDelegate = false
+			}
+		},
+
+		/**
+		 * Execute the add-delegate operation.
+		 *
+		 * @param {'write'|'read'} permission The permission level to grant
+		 */
+		async confirmAddDelegate(permission) {
+			if (!this.selectedUser) {
+				return
+			}
+			this.addLoading = true
+			const user = this.selectedUser
+			this.showAddDelegate = false
+			try {
+				await this.delegationStore.addDelegate({ principalUrl: user.url, permission })
+				const label = permission === 'read'
+					? this.t('calendar', '{name} can now view your calendars.', { name: user.displayname || user.principalId })
+					: this.t('calendar', '{name} can now act on your behalf.', { name: user.displayname || user.principalId })
+				showSuccess(label)
+			} catch (error) {
+				logger.error('Failed to add delegate', { error })
+				showError(this.t('calendar', 'Could not add delegate.'))
+			} finally {
+				this.addLoading = false
+				this.selectedUser = null
+			}
+		},
+
+		/**
+		 * Filter function for NcSelect to match against displayname, email, or principalId.
+		 *
+		 * @param {object} option The option object
+		 * @param {string} label The label value
+		 * @param {string} search The current search term
+		 * @return {boolean}
+		 */
+		filterSearchResults(option, label, search) {
+			if (!search) {
+				return true
+			}
+			const term = search.toLowerCase()
+			return (label && label.toLowerCase().includes(term))
+				|| (option.emailAddress && option.emailAddress.toLowerCase().includes(term))
+				|| (option.principalId && option.principalId.toLowerCase().includes(term))
+		},
+
+		/**
+		 * Search for users by display name or email.
+		 */
+		onSearch: debounce(async function(query) {
+			if (!query) {
+				this.searchResults = []
+				return
+			}
+
+			this.searchLoading = true
+			try {
+				const results = await principalPropertySearchByDisplaynameOrEmail(query)
+				const currentUser = this.principalsStore.getCurrentUserPrincipal
+				const existingDelegateUrls = this.delegationStore.delegates.map((d) => d.url)
+
+				this.searchResults = results
+					.filter((result) => {
+						// Only include individual users (not rooms/resources/groups)
+						if (result.calendarUserType !== 'INDIVIDUAL') {
+							return false
+						}
+						// Exclude the current user
+						if (currentUser && result.principalUrl === currentUser.url) {
+							return false
+						}
+						// Exclude already-existing delegates (both editors and viewers)
+						if (existingDelegateUrls.includes(result.principalUrl)) {
+							return false
+						}
+						return true
+					})
+					.map((result) => ({
+						url: result.principalUrl,
+						displayname: result.displayname,
+						emailAddress: result.email,
+						principalId: result.userId,
+					}))
+			} catch (error) {
+				logger.error('User search failed', { error })
+				this.searchResults = []
+			} finally {
+				this.searchLoading = false
+			}
+		}, 300),
+	},
+}
+</script>
+
+<style lang="scss" scoped>
+.delegation-settings {
+	&__loading {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+	}
+
+	&__list {
+		list-style: none;
+		padding: 0;
+		margin: 0 0 calc(var(--default-grid-baseline) * 2);
+	}
+
+	&__empty {
+		color: var(--color-text-maxcontrast);
+		font-style: italic;
+		margin: calc(var(--default-grid-baseline) * 2) 0;
+	}
+
+	&__add-button {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+	}
+}
+
+.delegation-add {
+	padding: var(--default-grid-baseline) 0;
+
+	&__select {
+		width: 100%;
+	}
+
+	&__description {
+		margin-top: calc(var(--default-grid-baseline) * 3);
+		color: var(--color-text-maxcontrast);
+	}
+
+	&__option {
+		display: flex;
+		align-items: center;
+		gap: calc(var(--default-grid-baseline) * 2);
+		width: 100%;
+	}
+
+	&__option-label {
+		display: flex;
+		flex-direction: column;
+	}
+
+	&__option-email {
+		color: var(--color-text-lighter);
+	}
+}
+</style>
diff --git a/src/components/Editor/CalendarPickerHeader.vue b/src/components/Editor/CalendarPickerHeader.vue
index 494287d10d..f342592116 100644
--- a/src/components/Editor/CalendarPickerHeader.vue
+++ b/src/components/Editor/CalendarPickerHeader.vue
@@ -34,7 +34,18 @@
 					@click="$emit('update:value', calendar)">
 					<template #icon>
 						<div class="calendar-picker-header__icon">
+							<NcAvatar
+								v-if="calendar.isSharedWithMe || calendar.isDelegated"
+								class="calendar-picker-header__picker__option__avatar"
+								:title="getOwnerDisplayName(calendar)"
+								:disableMenu="true"
+								:disableTooltip="true"
+								:hideStatus="true"
+								:user="getOwnerUserId(calendar)"
+								:displayName="getOwnerDisplayName(calendar)"
+								:size="20" />
 							<div
+								v-else
 								class="calendar-picker-header__icon__dot"
 								:style="{ 'background-color': calendar.color }" />
 						</div>
@@ -43,17 +54,29 @@
 				</NcActionButton>
 			</template>
 		</NcActions>
+		<NcAvatar
+			v-if="value.isSharedWithMe || value.isDelegated"
+			class="calendar-picker-header__avatar"
+			:disableMenu="true"
+			:title="ownerDisplayName"
+			:disableTooltip="true"
+			:user="ownerUserId"
+			:displayName="ownerDisplayName"
+			:size="24" />
 	</div>
 </template>
 
 <script>
-import { NcActionButton, NcActions } from '@nextcloud/vue'
+import { NcActionButton, NcActions, NcAvatar } from '@nextcloud/vue'
+import { mapStores } from 'pinia'
+import usePrincipalsStore from '../../store/principals.js'
 
 export default {
 	name: 'CalendarPickerHeader',
 	components: {
 		NcActions,
 		NcActionButton,
+		NcAvatar,
 	},
 
 	props: {
@@ -79,12 +102,40 @@ export default {
 	},
 
 	computed: {
+		...mapStores(usePrincipalsStore),
 		/**
 		 * @return {boolean}
 		 */
 		isDisabled() {
 			return this.isReadOnly || this.calendars.length < 2
 		},
+
+		/**
+		 * Get the principal object of the calendar's owner
+		 *
+		 * @return {null | object}
+		 */
+		ownerPrincipal() {
+			return this.principalsStore.getPrincipalByUrl(this.value.owner)
+		},
+
+		/**
+		 * Gets the user-id of the calendar's owner
+		 *
+		 * @return {null | string}
+		 */
+		ownerUserId() {
+			return this.ownerPrincipal?.userId ?? null
+		},
+
+		/**
+		 * Gets the display name of the calendar's owner
+		 *
+		 * @return {null | string}
+		 */
+		ownerDisplayName() {
+			return this.ownerPrincipal?.displayname ?? null
+		},
 	},
 
 	mounted() {
@@ -93,6 +144,28 @@ export default {
 		const menuDownIconUrl = 'url(data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAyNCAyNCI+PHBhdGggZD0iTTcsMTBMMTIsMTVMMTcsMTBIN1oiIC8+PC9zdmc+)'
 		this.$el.style.setProperty('--mdi-menu-down', menuDownIconUrl)
 	},
+
+	methods: {
+		/**
+		 * Gets the user-id of the given calendar's owner
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getOwnerUserId(calendar) {
+			return this.principalsStore.getPrincipalByUrl(calendar.owner)?.userId ?? null
+		},
+
+		/**
+		 * Gets the display name of the given calendar's owner
+		 *
+		 * @param {object} calendar The calendar object
+		 * @return {null | string}
+		 */
+		getOwnerDisplayName(calendar) {
+			return this.principalsStore.getPrincipalByUrl(calendar.owner)?.displayname ?? null
+		},
+	},
 }
 </script>
 
@@ -142,6 +215,10 @@ export default {
 			:deep(button) {
 				align-items: center !important;
 			}
+
+			&__avatar {
+				margin: auto;
+			}
 		}
 
 		// Fix long calendar name ellipsis
@@ -162,6 +239,12 @@ export default {
 		}
 	}
 
+	&__avatar {
+		flex-shrink: 0;
+		align-self: center;
+		margin-inline-start: var(--default-grid-baseline);
+	}
+
 	&__icon {
 		display: flex;
 		align-items: center;
diff --git a/src/components/Shared/CalendarPicker.vue b/src/components/Shared/CalendarPicker.vue
index 91faa0ceea..cebc317057 100644
--- a/src/components/Shared/CalendarPicker.vue
+++ b/src/components/Shared/CalendarPicker.vue
@@ -21,6 +21,7 @@
 				:color="getCalendarById(id).color"
 				:displayName="getCalendarById(id).displayName"
 				:isSharedWithMe="getCalendarById(id).isSharedWithMe"
+				:isDelegated="getCalendarById(id).isDelegated"
 				:owner="getCalendarById(id).owner" />
 		</template>
 		<template #selected-option="{ id }">
@@ -28,6 +29,7 @@
 				:color="getCalendarById(id).color"
 				:displayName="getCalendarById(id).displayName"
 				:isSharedWithMe="getCalendarById(id).isSharedWithMe"
+				:isDelegated="getCalendarById(id).isDelegated"
 				:owner="getCalendarById(id).owner" />
 		</template>
 	</NcSelect>
diff --git a/src/components/Shared/CalendarPickerOption.vue b/src/components/Shared/CalendarPickerOption.vue
index 1c528f6fe8..72871f3b1e 100644
--- a/src/components/Shared/CalendarPickerOption.vue
+++ b/src/components/Shared/CalendarPickerOption.vue
@@ -14,7 +14,7 @@
 		</span>
 
 		<Avatar
-			v-if="isSharedWithMe"
+			v-if="isSharedWithMe || isDelegated"
 			class="calendar-picker-option__avatar"
 			:disableMenu="true"
 			:disableTooltip="true"
@@ -55,6 +55,11 @@ export default {
 			type: Boolean,
 			required: true,
 		},
+
+		isDelegated: {
+			type: Boolean,
+			default: false,
+		},
 	},
 
 	computed: {
diff --git a/src/models/calendar.js b/src/models/calendar.js
index aaa34eeffa..dc9e9419da 100644
--- a/src/models/calendar.js
+++ b/src/models/calendar.js
@@ -45,6 +45,8 @@ function getDefaultCalendarObject(props = {}) {
 		order: 0,
 		// Whether or not the calendar is shared with me
 		isSharedWithMe: false,
+		// Whether or not the calendar belongs to a user who delegated to me
+		isDelegated: false,
 		// Whether or not the calendar can be shared by me
 		canBeShared: false,
 		// Whether or not the calendar can be published by me
diff --git a/src/services/caldavService.js b/src/services/caldavService.js
index 851cebb78d..25332359e8 100644
--- a/src/services/caldavService.js
+++ b/src/services/caldavService.js
@@ -250,6 +250,17 @@ async function findPrincipalsInCollection(url, options = {}) {
 	return getClient().findPrincipalsInCollection(url, options)
 }
 
+/**
+ * Fetches all calendars from a calendar home at an arbitrary URL.
+ * Used to load calendars from another user's calendar home when acting as their proxy.
+ * @param {string} calendarHomeUrl Absolute URL of the calendar home to fetch from
+ * @return {Promise<Calendar[]>} Raw cdav-library Calendar objects
+ */
+async function findCalendarsAtUrl(calendarHomeUrl) {
+	const calendarHome = getClient().getCalendarHomeForUrl(calendarHomeUrl)
+	return calendarHome.findAllCalendars()
+}
+
 export {
 	advancedPrincipalPropertySearch,
 	createCalendar,
@@ -258,12 +269,14 @@ export {
 	findAll,
 	findAllCalendars,
 	findAllDeletedCalendars,
+	findCalendarsAtUrl,
 	findPrincipalByUrl,
 	findPrincipalsInCollection,
 	findPublicCalendarsByTokens,
 	findSchedulingInbox,
 	findSchedulingOutbox,
 	getBirthdayCalendar,
+	getClient,
 	getCurrentUserPrincipal,
 	initializeClientForPublicView,
 	initializeClientForUserView,
diff --git a/src/store/delegation.js b/src/store/delegation.js
new file mode 100644
index 0000000000..ff0cf6c66c
--- /dev/null
+++ b/src/store/delegation.js
@@ -0,0 +1,227 @@
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+import { showError } from '@nextcloud/dialogs'
+import { translate as t } from '@nextcloud/l10n'
+import { defineStore } from 'pinia'
+import { mapDavCollectionToCalendar } from '../models/calendar.js'
+import { mapDavToPrincipal } from '../models/principal.js'
+import { findCalendarsAtUrl, findPrincipalByUrl, getClient } from '../services/caldavService.js'
+import logger from '../utils/logger.js'
+import useCalendarsStore from './calendars.js'
+import usePrincipalsStore from './principals.js'
+
+export default defineStore('delegation', {
+	state: () => {
+		return {
+			/**
+			 * List of principal objects that the current user has delegated to.
+			 * Each entry has the principal fields plus a `permission` field ('write'|'read').
+			 *
+			 * @type {object[]}
+			 */
+			delegates: [],
+
+			/**
+			 * Users who have granted the current user proxy access, with permission level.
+			 * Each entry: { principalUrl: string, permission: 'write'|'read' }
+			 *
+			 * @type {Array<{principalUrl: string, permission: 'write'|'read'}>}
+			 */
+			delegators: [],
+		}
+	},
+
+	getters: {
+		/**
+		 * Whether any delegated calendars exist (i.e. the current user is a delegate for someone).
+		 *
+		 * @param {object} state The store state
+		 * @return {boolean}
+		 */
+		hasDelegatedCalendars: (state) => state.delegators.length > 0,
+	},
+
+	actions: {
+		/**
+		 * Fetch the current user's delegates (members of their calendar-proxy-write
+		 * and calendar-proxy-read groups) and resolve their principal details.
+		 *
+		 * @return {Promise<void>}
+		 */
+		async fetchDelegates() {
+			const principalsStore = usePrincipalsStore()
+			const currentUser = principalsStore.getCurrentUserPrincipal
+			if (!currentUser?.url) {
+				return
+			}
+
+			const baseUrl = currentUser.url.replace(/\/?$/, '')
+			const proxyWriteGroupUrl = baseUrl + '/calendar-proxy-write'
+			const proxyReadGroupUrl = baseUrl + '/calendar-proxy-read'
+
+			let writeUrls = []
+			let readUrls = []
+			try {
+				[writeUrls, readUrls] = await Promise.all([
+					getClient().getDelegateUrls(proxyWriteGroupUrl),
+					getClient().getDelegateUrls(proxyReadGroupUrl),
+				])
+			} catch (error) {
+				logger.error('Could not fetch delegate URLs', { error })
+				return
+			}
+
+			const delegates = []
+
+			for (const url of writeUrls) {
+				try {
+					const dav = await findPrincipalByUrl(url)
+					if (dav) {
+						delegates.push({ ...mapDavToPrincipal(dav), permission: 'write' })
+					}
+				} catch (error) {
+					logger.error('Could not resolve write delegate principal', { url, error })
+				}
+			}
+
+			for (const url of readUrls) {
+				try {
+					const dav = await findPrincipalByUrl(url)
+					if (dav) {
+						delegates.push({ ...mapDavToPrincipal(dav), permission: 'read' })
+					}
+				} catch (error) {
+					logger.error('Could not resolve read delegate principal', { url, error })
+				}
+			}
+
+			this.delegates = delegates
+			logger.debug('Fetched delegates', { delegates: this.delegates })
+		},
+
+		/**
+		 * Fetch the principal URLs and permission level of users who have granted
+		 * the current user proxy access (both read and write).
+		 *
+		 * @return {Promise<void>}
+		 */
+		async fetchDelegators() {
+			const principalsStore = usePrincipalsStore()
+			const currentUser = principalsStore.getCurrentUserPrincipal
+			if (!currentUser?.url) {
+				return
+			}
+
+			try {
+				this.delegators = await getClient().getDelegatorsWithPermission(currentUser.url)
+				logger.debug('Fetched delegators', { delegators: this.delegators })
+			} catch (error) {
+				logger.error('Could not fetch delegator information', { error })
+			}
+		},
+
+		/**
+		 * Add a user as a delegate with the given permission level.
+		 *
+		 * @param {object} data The destructuring object
+		 * @param {string} data.principalUrl Absolute URL of the principal to add
+		 * @param {'write'|'read'} data.permission The permission level to grant
+		 * @return {Promise<void>}
+		 */
+		async addDelegate({ principalUrl, permission = 'write' }) {
+			const principalsStore = usePrincipalsStore()
+			const currentUser = principalsStore.getCurrentUserPrincipal
+			if (!currentUser?.url) {
+				return
+			}
+
+			const baseUrl = currentUser.url.replace(/\/?$/, '')
+			const proxyGroupUrl = permission === 'read'
+				? baseUrl + '/calendar-proxy-read'
+				: baseUrl + '/calendar-proxy-write'
+			await getClient().addDelegate(proxyGroupUrl, principalUrl)
+			await this.fetchDelegates()
+		},
+
+		/**
+		 * Remove a delegate from whichever proxy group(s) they are in.
+		 *
+		 * @param {object} data The destructuring object
+		 * @param {string} data.principalUrl Absolute URL of the principal to remove
+		 * @return {Promise<void>}
+		 */
+		async removeDelegate({ principalUrl }) {
+			const principalsStore = usePrincipalsStore()
+			const currentUser = principalsStore.getCurrentUserPrincipal
+			if (!currentUser?.url) {
+				return
+			}
+
+			const baseUrl = currentUser.url.replace(/\/?$/, '')
+			// Find the delegate's current permission so we remove from the right group.
+			const existing = this.delegates.find((d) => d.url === principalUrl)
+			const permission = existing?.permission ?? 'write'
+
+			const proxyGroupUrl = permission === 'read'
+				? baseUrl + '/calendar-proxy-read'
+				: baseUrl + '/calendar-proxy-write'
+			await getClient().removeDelegate(proxyGroupUrl, principalUrl)
+			this.delegates = this.delegates.filter((d) => d.url !== principalUrl)
+		},
+
+		/**
+		 * Fetch all calendars from delegators' calendar homes and add them to the
+		 * calendars store so they participate in normal event fetching and rendering.
+		 * The calendars are tagged with isDelegated=true so CalendarList can show them
+		 * in their own section.
+		 *
+		 * Read-only delegators' calendars are additionally marked readOnly=true so they
+		 * are excluded from the calendar picker (which only lists writable calendars).
+		 *
+		 * @return {Promise<void>}
+		 */
+		async fetchDelegatedCalendars() {
+			if (!this.delegators.length) {
+				return
+			}
+
+			const principalsStore = usePrincipalsStore()
+			const calendarsStore = useCalendarsStore()
+			const currentUser = principalsStore.getCurrentUserPrincipal
+
+			for (const { principalUrl: delegatorPrincipalUrl, permission } of this.delegators) {
+				const calendarHomeUrl = await getClient().getCalendarHomeUrlForPrincipal(delegatorPrincipalUrl)
+				if (!calendarHomeUrl) {
+					logger.warn('Could not determine calendar home URL for delegator', { delegatorPrincipalUrl })
+					showError(t('calendar', 'Could not load delegated calendars. Make sure the server supports calendar delegation.'))
+					continue
+				}
+
+				try {
+					const rawCalendars = await findCalendarsAtUrl(calendarHomeUrl)
+					const mappedCalendars = rawCalendars
+						.map((cal) => mapDavCollectionToCalendar(cal, currentUser))
+						.map((cal) => ({
+							...cal,
+							isDelegated: true,
+							// Read-only proxy access: prevent editing and hide from calendar picker
+							...(permission === 'read' ? { readOnly: true } : {}),
+						}))
+
+					for (const calendar of mappedCalendars) {
+						if (!calendarsStore.getCalendarById(calendar.id)) {
+							calendarsStore.addCalendarMutation({ calendar })
+						}
+					}
+
+					logger.debug('Fetched delegated calendars from', { calendarHomeUrl, permission, count: mappedCalendars.length })
+				} catch (error) {
+					logger.error('Could not fetch calendars for delegator', { delegatorPrincipalUrl, error })
+					showError(t('calendar', 'Could not load delegated calendars. Make sure the server supports calendar delegation.'))
+				}
+			}
+		},
+	},
+})
diff --git a/src/views/Calendar.vue b/src/views/Calendar.vue
index 81ef0c440f..179d674a00 100644
--- a/src/views/Calendar.vue
+++ b/src/views/Calendar.vue
@@ -136,6 +136,7 @@ import { isNotifyPushAvailable, registerNotifyPushSyncListener } from '../servic
 import getTimezoneManager from '../services/timezoneDataProviderService.js'
 import useCalendarObjectsStore from '../store/calendarObjects.js'
 import useCalendarsStore from '../store/calendars.js'
+import useDelegationStore from '../store/delegation.js'
 import useFetchedTimeRangesStore from '../store/fetchedTimeRanges.js'
 import usePrincipalsStore from '../store/principals.js'
 import useSettingsStore from '../store/settings.js'
@@ -222,6 +223,7 @@ export default {
 			usePrincipalsStore,
 			useSettingsStore,
 			useWidgetStore,
+			useDelegationStore,
 		),
 
 		...mapState(useSettingsStore, {
@@ -386,6 +388,10 @@ export default {
 				})
 			}
 
+			// Load delegation info: who has delegated their calendars to the current user
+			await this.delegationStore.fetchDelegators()
+			await this.delegationStore.fetchDelegatedCalendars()
+
 			this.loadingCalendars = false
 		}
 	},
diff --git a/tests/javascript/unit/models/calendar.test.js b/tests/javascript/unit/models/calendar.test.js
index 164747461b..6e60b63f2c 100644
--- a/tests/javascript/unit/models/calendar.test.js
+++ b/tests/javascript/unit/models/calendar.test.js
@@ -32,6 +32,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			url: '',
 			readOnly: false,
 			order: 0,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canBeShared: false,
 			canBePublished: false,
@@ -67,6 +68,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			url: '',
 			readOnly: false,
 			order: 0,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canBeShared: false,
 			canBePublished: false,
@@ -117,6 +119,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -169,6 +172,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -219,6 +223,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -269,6 +274,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: true,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -319,6 +325,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -369,6 +376,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -419,6 +427,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -469,6 +478,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -575,6 +585,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -697,6 +708,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: true,
 			canCreateObject: false,
 			canDeleteObject: false,
@@ -748,6 +760,7 @@ describe('Test suite: Calendar model (models/calendar.js)', () => {
 			supportsEvents: true,
 			supportsJournals: false,
 			supportsTasks: false,
+			isDelegated: false,
 			isSharedWithMe: false,
 			canCreateObject: false,
 			canDeleteObject: false,