diff --git a/docs/MoltenVK.md b/docs/MoltenVK.md
new file mode 100644
index 00000000..3c8d8bee
--- /dev/null
+++ b/docs/MoltenVK.md
@@ -0,0 +1,20 @@
+# Enabling Vulkan on macOS with MoltenVK
+
+> Note: MoltenVK uses SPIRV-Cross to convert SPIRV shaders to the Metal shading
+> language. This increases the mismatch between shader behavior, and as a result
+> many of the tests in this suite have known failures or behavior differences.
+
+To enable Vulkan testing on macOS you first need to download and install the
+Vulkan SDK from [here](https://vulkan.lunarg.com).
+
+By default the SDK installs into your home directory under
+`~/VulkanSDK/${SDK_Version}/macOS`. For CMake to find the SDK you either need to
+set the `VULKAN_SDK` environment variable to the macOS subdirectory of the
+VulkanSDK installation you wish to use. You also need to run `sudo
+~/VulkanSDK/${SDK_Version}/install_vulkan.py --force-install`, to install the
+development binaries into `/usr/local/...` so that launched applications can
+find them.
+
+Once the SDK is installed and exposed to CMake, a clean configuration will
+detect Vulkan and the MoltenVK portability layer and enable the Vulkan test
+configurations.
diff --git a/lib/API/VK/Device.cpp b/lib/API/VK/Device.cpp
index 4dc58c91..4a0381c5 100644
--- a/lib/API/VK/Device.cpp
+++ b/lib/API/VK/Device.cpp
@@ -1267,7 +1267,7 @@ class VKContext {
     VkResult Res = vkCreateInstance(&CreateInfo, NULL, &Instance);
     if (Res == VK_ERROR_INCOMPATIBLE_DRIVER)
       return llvm::createStringError(std::errc::no_such_device,
-                                     "Cannot find a compatible Vulkan device");
+                                     "Cannot find a base Vulkan device");
     if (Res)
       return llvm::createStringError(std::errc::no_such_device,
                                      "Unknown Vulkan initialization error: %d",
diff --git a/test/Feature/HLSLLib/cosh.16.test b/test/Feature/HLSLLib/cosh.16.test
index ea4bb502..6e59be7c 100644
--- a/test/Feature/HLSLLib/cosh.16.test
+++ b/test/Feature/HLSLLib/cosh.16.test
@@ -61,6 +61,9 @@ DescriptorSets:
 ...
 #--- end
 
+# https://github.com/KhronosGroup/SPIRV-Cross/issues/2507
+# XFAIL: Vulkan-Darwin
+
 # REQUIRES: Half
 # RUN: split-file %s %t
 # RUN: %dxc_target -enable-16bit-types -T cs_6_5 -Fo %t.o %t/source.hlsl
diff --git a/test/Feature/HLSLLib/sign.32.test b/test/Feature/HLSLLib/sign.32.test
index 88cef099..295f5a93 100644
--- a/test/Feature/HLSLLib/sign.32.test
+++ b/test/Feature/HLSLLib/sign.32.test
@@ -74,7 +74,7 @@ Buffers:
   - Name: Out2
     Format: Int32
     Stride: 16
-    ZeroInitSize: 48 
+    ZeroInitSize: 48
   - Name: ExpectedOut2 # The result we expect
     Format: Int32
     Stride: 16
@@ -82,7 +82,7 @@ Buffers:
   - Name: Out3
     Format: Int32
     Stride: 16
-    ZeroInitSize: 48 
+    ZeroInitSize: 48
   - Name: ExpectedOut3 # The result we expect
     Format: Int32
     Stride: 16
@@ -176,6 +176,11 @@ DescriptorSets:
 # https://github.com/microsoft/DirectXShaderCompiler/issues/7512
 # XFAIL: DXC-Vulkan
 
+# https://github.com/llvm/llvm-project/issues/149722
+# We're generating invalid SPIRV for this. I have _no_ idea why this isn't
+# failing on all Clang Vulkan tests.
+# XFAIL: Clang && Vulkan-Darwin
+
 # RUN: split-file %s %t
 # RUN: %dxc_target -T cs_6_5 -Fo %t.o %t/source.hlsl
 # RUN: %offloader %t/pipeline.yaml %t.o
diff --git a/test/Feature/HLSLLib/sinh.16.test b/test/Feature/HLSLLib/sinh.16.test
index 6a9de395..8d6f7ee1 100644
--- a/test/Feature/HLSLLib/sinh.16.test
+++ b/test/Feature/HLSLLib/sinh.16.test
@@ -61,6 +61,9 @@ DescriptorSets:
 ...
 #--- end
 
+# https://github.com/KhronosGroup/SPIRV-Cross/issues/2507
+# XFAIL: Vulkan-Darwin
+
 # REQUIRES: Half
 # RUN: split-file %s %t
 # RUN: %dxc_target -enable-16bit-types -T cs_6_5 -Fo %t.o %t/source.hlsl
diff --git a/test/Feature/HLSLLib/tanh.16.test b/test/Feature/HLSLLib/tanh.16.test
index 6e4fc9e5..26efebf7 100644
--- a/test/Feature/HLSLLib/tanh.16.test
+++ b/test/Feature/HLSLLib/tanh.16.test
@@ -61,6 +61,9 @@ DescriptorSets:
 ...
 #--- end
 
+# https://github.com/KhronosGroup/SPIRV-Cross/issues/2507
+# XFAIL: Vulkan-Darwin
+
 # REQUIRES: Half
 # RUN: split-file %s %t
 # RUN: %dxc_target -enable-16bit-types -T cs_6_5 -Fo %t.o %t/source.hlsl
diff --git a/test/UseCase/particle-life.test b/test/UseCase/particle-life.test
index 63722339..1c8d4d29 100644
--- a/test/UseCase/particle-life.test
+++ b/test/UseCase/particle-life.test
@@ -357,6 +357,9 @@ DescriptorSets:
 # https://github.com/llvm/offload-test-suite/issues/55
 # UNSUPPORTED: Metal
 
+# No idea what is going on here, but the results are _way_ off.
+# XFAIL: Vulkan-Darwin
+
 # RUN: split-file %s %t
 # RUN: %if !Vulkan %{ %dxc_target -T cs_6_0 -Fo %t.o %t/particle-life.hlsl %}
 # RUN: %if Vulkan %{ %dxc_target -T cs_6_0 -fspv-target-env=vulkan1.3 -fvk-use-scalar-layout -Fo %t.o %t/particle-life.hlsl %}
diff --git a/test/lit.cfg.py b/test/lit.cfg.py
index 9cd3a943..23968fe3 100644
--- a/test/lit.cfg.py
+++ b/test/lit.cfg.py
@@ -51,6 +51,7 @@
 def setDeviceFeatures(config, device, compiler):
     API = device["API"]
     config.available_features.add(API)
+    config.available_features.add("%s-%s" % (API, config.offloadtest_os))
     if "Microsoft Basic Render Driver" in device["Description"]:
         config.available_features.add("%s-WARP" % API)
     if "Intel" in device["Description"]:
diff --git a/test/lit.site.cfg.py.in b/test/lit.site.cfg.py.in
index b670e195..83d0a62b 100644
--- a/test/lit.site.cfg.py.in
+++ b/test/lit.site.cfg.py.in
@@ -16,6 +16,7 @@ config.offloadtest_suite = "@suite@"
 config.offloadtest_enable_d3d12 = @TEST_d3d12@
 config.offloadtest_enable_vulkan = @TEST_vk@
 config.offloadtest_enable_metal = @TEST_mtl@
+config.offloadtest_os = "@CMAKE_SYSTEM_NAME@"
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
diff --git a/tools/api-query/CMakeLists.txt b/tools/api-query/CMakeLists.txt
index 6b060293..9e55fb2f 100644
--- a/tools/api-query/CMakeLists.txt
+++ b/tools/api-query/CMakeLists.txt
@@ -2,3 +2,9 @@ add_offloadtest_tool(api-query
               api-query.cpp)
 
 target_link_libraries(api-query PRIVATE LLVMSupport OffloadTestAPI)
+
+if (APPLE AND OFFLOADTEST_ENABLE_VULKAN)
+  get_filename_component(_Vulkan_LIB_DIR ${Vulkan_LIBRARY} DIRECTORY)
+  set_property(TARGET api-query APPEND_STRING PROPERTY
+               LINK_FLAGS " -Wl,-rpath,${_Vulkan_LIB_DIR} ")
+endif()
diff --git a/tools/offloader/CMakeLists.txt b/tools/offloader/CMakeLists.txt
index d19487d7..d4c6120b 100644
--- a/tools/offloader/CMakeLists.txt
+++ b/tools/offloader/CMakeLists.txt
@@ -6,3 +6,9 @@ target_link_libraries(offloader PRIVATE
                       OffloadTestAPI
                       OffloadTestImage
                       OffloadTestSupport)
+
+if (APPLE AND OFFLOADTEST_ENABLE_VULKAN)
+  get_filename_component(_Vulkan_LIB_DIR ${Vulkan_LIBRARY} DIRECTORY)
+  set_property(TARGET offloader APPEND_STRING PROPERTY
+               LINK_FLAGS " -Wl,-rpath,${_Vulkan_LIB_DIR} ")
+endif()