diff --git a/uefi-raw/src/protocol/iommu.rs b/uefi-raw/src/protocol/iommu.rs
new file mode 100644
index 000000000..fbc0aabab
--- /dev/null
+++ b/uefi-raw/src/protocol/iommu.rs
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use crate::table::boot::{AllocateType, MemoryType};
+use crate::{Guid, Handle, Status, guid};
+use bitflags::bitflags;
+use core::ffi::c_void;
+
+use crate::newtype_enum;
+
+/// EDKII IOMMU Protocol GUID
+impl EdkiiIommuProtocol {
+    pub const GUID: Guid = guid!("4e939de9-d948-4b0f-88ed-e6e1ce517c1e");
+}
+
+#[derive(Debug)]
+#[repr(C)]
+pub struct EdkiiIommuProtocol {
+    pub revision: u64,
+    pub set_attribute: unsafe extern "efiapi" fn(
+        this: *const Self,
+        device_handle: Handle,
+        mapping: *mut c_void,
+        iommu_access: EdkiiIommuAccess,
+    ) -> Status,
+    pub map: unsafe extern "efiapi" fn(
+        this: *const Self,
+        operation: EdkiiIommuOperation,
+        host_address: *mut c_void,
+        number_of_bytes: *mut usize,
+        device_address: *mut u64,
+        mapping: *mut *mut c_void,
+    ) -> Status,
+    pub unmap: unsafe extern "efiapi" fn(this: *const Self, mapping: *mut c_void) -> Status,
+    pub allocate_buffer: unsafe extern "efiapi" fn(
+        this: *const Self,
+        allocate_type: AllocateType,
+        memory_type: MemoryType,
+        pages: usize,
+        host_address: *mut *mut c_void,
+        attributes: EdkiiIommuAttribute,
+    ) -> Status,
+    pub free_buffer: unsafe extern "efiapi" fn(
+        this: *const Self,
+        pages: usize,
+        host_address: *mut c_void,
+    ) -> Status,
+}
+
+newtype_enum! {
+    /// IOMMU Operation for Map (matches EDKII_IOMMU_OPERATION)
+    pub enum EdkiiIommuOperation: u32 => {
+        /// A read operation from system memory by a bus master that is not capable of producing PCI dual address cycles.
+        BUS_MASTER_READ = 0,
+        /// A write operation to system memory by a bus master that is not capable of producing PCI dual address cycles.
+        BUS_MASTER_WRITE = 1,
+        /// Provides both read and write access to system memory by both the processor and a bus master that is not capable of producing PCI dual address cycles.
+        BUS_MASTER_COMMON_BUFFER = 2,
+        /// A read operation from system memory by a bus master that is capable of producing PCI dual address cycles.
+        BUS_MASTER_READ64 = 3,
+        /// A write operation to system memory by a bus master that is capable of producing PCI dual address cycles.
+        BUS_MASTER_WRITE64 = 4,
+        /// Provides both read and write access to system memory by both the processor and a bus master that is capable of producing PCI dual address cycles.
+        BUS_MASTER_COMMON_BUFFER64 = 5,
+        /// Maximum value (not a valid operation, for bounds checking)
+        MAXIMUM = 6,
+    }
+}
+
+/// EDKII IOMMU protocol revision constant
+pub const EDKII_IOMMU_PROTOCOL_REVISION: u64 = 0x0001_0000;
+
+bitflags! {
+    /// EDKII IOMMU attribute flags
+    #[repr(transparent)]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct EdkiiIommuAttribute: u64 {
+        /// Memory is write-combined
+        const MEMORY_WRITE_COMBINE   = 0x0080;
+        /// Memory is cached
+        const MEMORY_CACHED          = 0x0800;
+        /// Dual address cycle supported
+        const DUAL_ADDRESS_CYCLE     = 0x8000;
+    }
+}
+
+impl EdkiiIommuAttribute {
+    /// Valid attributes for allocate_buffer
+    pub const VALID_FOR_ALLOCATE_BUFFER: Self = Self::from_bits_truncate(
+        Self::MEMORY_WRITE_COMBINE.bits()
+            | Self::MEMORY_CACHED.bits()
+            | Self::DUAL_ADDRESS_CYCLE.bits(),
+    );
+
+    /// Invalid attributes for allocate_buffer (all bits except valid)
+    pub const INVALID_FOR_ALLOCATE_BUFFER: Self =
+        Self::from_bits_truncate(!Self::VALID_FOR_ALLOCATE_BUFFER.bits());
+}
+
+bitflags! {
+    /// EDKII IOMMU access flags for SetAttribute
+    #[repr(transparent)]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct EdkiiIommuAccess: u64 {
+        /// Read access
+        const READ  = 0x1;
+        /// Write access
+        const WRITE = 0x2;
+    }
+}
diff --git a/uefi-raw/src/protocol/mod.rs b/uefi-raw/src/protocol/mod.rs
index f634b7ae8..0d2ecf1de 100644
--- a/uefi-raw/src/protocol/mod.rs
+++ b/uefi-raw/src/protocol/mod.rs
@@ -33,6 +33,7 @@ pub mod driver;
 pub mod file_system;
 pub mod firmware_volume;
 pub mod hii;
+pub mod iommu;
 pub mod loaded_image;
 pub mod media;
 pub mod memory_protection;