diff --git a/Docs/Whats_New.md b/Docs/Whats_New.md
index 48081c1..54307db 100644
--- a/Docs/Whats_New.md
+++ b/Docs/Whats_New.md
@@ -23,6 +23,10 @@
 	  including support for GCD and Mach semaphores)
 	- `VK_KHR_external_fence_capabilities` (non-functional groundwork for future
 	  extensions, including support for GCD and Mach semaphores)
+	- `VK_KHR_external_semaphore` (non-functional groundwork for future
+	  `MTLSharedEvent` Vulkan extension)
+	- `VK_KHR_external_semaphore_capabilities` (non-functional groundwork for
+	  future `MTLSharedEvent` Vulkan extension)
 	- `VK_KHR_multiview`
 - Improve performance of tessellation control pipeline stage by processing multiple 
   patches per workgroup.
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.h b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.h
index deabd83..9e78715 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.h
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.h
@@ -141,6 +141,10 @@
 	void getExternalFenceProperties(const VkPhysicalDeviceExternalFenceInfo* pExternalFenceInfo,
 									VkExternalFenceProperties* pExternalFenceProperties);
 
+	/** Populates the external semaphore properties supported on this device. */
+	void getExternalSemaphoreProperties(const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+										VkExternalSemaphoreProperties* pExternalSemaphoreProperties);
+
 #pragma mark Surfaces
 
 	/**
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
index ceb59c0..71fb97d 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKDevice.mm
@@ -603,6 +603,15 @@
 	pExternalFenceProperties->pNext = next;
 }
 
+static const VkExternalSemaphoreProperties _emptyExtSemProps = {VK_STRUCTURE_TYPE_EXTERNAL_SEMAPHORE_PROPERTIES, nullptr, 0, 0, 0};
+
+void MVKPhysicalDevice::getExternalSemaphoreProperties(const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+													   VkExternalSemaphoreProperties* pExternalSemaphoreProperties) {
+	void* next = pExternalSemaphoreProperties->pNext;
+	*pExternalSemaphoreProperties = _emptyExtSemProps;
+	pExternalSemaphoreProperties->pNext = next;
+}
+
 
 #pragma mark Surfaces
 
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm b/MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm
index 851643e..9c9dfb1 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKInstance.mm
@@ -559,6 +559,7 @@
 	ADD_INST_EXT_ENTRY_POINT(vkEnumeratePhysicalDeviceGroupsKHR, KHR_DEVICE_GROUP_CREATION);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalFencePropertiesKHR, KHR_EXTERNAL_FENCE_CAPABILITIES);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalBufferPropertiesKHR, KHR_EXTERNAL_MEMORY_CAPABILITIES);
+	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceExternalSemaphorePropertiesKHR, KHR_EXTERNAL_SEMAPHORE_CAPABILITIES);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceFeatures2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceProperties2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);
 	ADD_INST_EXT_ENTRY_POINT(vkGetPhysicalDeviceFormatProperties2KHR, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2);
diff --git a/MoltenVK/MoltenVK/Layers/MVKExtensions.def b/MoltenVK/MoltenVK/Layers/MVKExtensions.def
index 3b73870..6b4be3b 100644
--- a/MoltenVK/MoltenVK/Layers/MVKExtensions.def
+++ b/MoltenVK/MoltenVK/Layers/MVKExtensions.def
@@ -51,6 +51,8 @@
 MVK_EXTENSION(KHR_external_fence_capabilities, KHR_EXTERNAL_FENCE_CAPABILITIES, INSTANCE)
 MVK_EXTENSION(KHR_external_memory, KHR_EXTERNAL_MEMORY, DEVICE)
 MVK_EXTENSION(KHR_external_memory_capabilities, KHR_EXTERNAL_MEMORY_CAPABILITIES, INSTANCE)
+MVK_EXTENSION(KHR_external_semaphore, KHR_EXTERNAL_SEMAPHORE, DEVICE)
+MVK_EXTENSION(KHR_external_semaphore_capabilities, KHR_EXTERNAL_SEMAPHORE_CAPABILITIES, INSTANCE)
 MVK_EXTENSION(KHR_get_memory_requirements2, KHR_GET_MEMORY_REQUIREMENTS_2, DEVICE)
 MVK_EXTENSION(KHR_get_physical_device_properties2, KHR_GET_PHYSICAL_DEVICE_PROPERTIES_2, INSTANCE)
 MVK_EXTENSION(KHR_get_surface_capabilities2, KHR_GET_SURFACE_CAPABILITIES_2, INSTANCE)
diff --git a/MoltenVK/MoltenVK/Vulkan/vulkan.mm b/MoltenVK/MoltenVK/Vulkan/vulkan.mm
index a35932e..2751526 100644
--- a/MoltenVK/MoltenVK/Vulkan/vulkan.mm
+++ b/MoltenVK/MoltenVK/Vulkan/vulkan.mm
@@ -2064,6 +2064,21 @@
 
 
 #pragma mark -
+#pragma mark VK_KHR_external_semaphore_capabilities extension
+
+MVK_PUBLIC_SYMBOL void vkGetPhysicalDeviceExternalSemaphorePropertiesKHR(
+	VkPhysicalDevice                             physicalDevice,
+	const VkPhysicalDeviceExternalSemaphoreInfo* pExternalSemaphoreInfo,
+	VkExternalSemaphoreProperties*               pExternalSemaphoreProperties) {
+
+	MVKTraceVulkanCallStart();
+	MVKPhysicalDevice* mvkPD = MVKPhysicalDevice::getMVKPhysicalDevice(physicalDevice);
+	mvkPD->getExternalSemaphoreProperties(pExternalSemaphoreInfo, pExternalSemaphoreProperties);
+	MVKTraceVulkanCallEnd();
+}
+
+
+#pragma mark -
 #pragma mark VK_KHR_get_memory_requirements2 extension
 
 MVK_PUBLIC_SYMBOL void vkGetBufferMemoryRequirements2KHR(