diff --git a/src/xrt/include/xrt/xrt_compiler.h b/src/xrt/include/xrt/xrt_compiler.h
index 6123e180c..fa619ddc4 100644
--- a/src/xrt/include/xrt/xrt_compiler.h
+++ b/src/xrt/include/xrt/xrt_compiler.h
@@ -22,7 +22,12 @@
 #include <intrin.h>
 // for atomic intrinsics
 #include "xrt_windows.h"
-#endif // _MSC_VER
+// Older MSVC versions do not have stdalign.h, define it manually using __declspec(align).
+#define XRT_ALIGNAS(n) __declspec(align(n))
+#else // _MSC_VER
+#include <stdalign.h>
+#define XRT_ALIGNAS(align) alignas(align)
+#endif
 
 #if (defined(__BYTE_ORDER) && __BYTE_ORDER == __BIG_ENDIAN) ||                                                         \
     (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) ||                                             \
diff --git a/src/xrt/include/xrt/xrt_compositor.h b/src/xrt/include/xrt/xrt_compositor.h
index f86ed3f4b..12926fd45 100644
--- a/src/xrt/include/xrt/xrt_compositor.h
+++ b/src/xrt/include/xrt/xrt_compositor.h
@@ -20,8 +20,6 @@
 #include "xrt/xrt_config_have.h"
 #include "xrt/xrt_windows.h"
 
-#include <stdalign.h>
-
 #if defined(XRT_HAVE_D3D11)
 #include <d3d11.h>
 #elif defined(XRT_DOXYGEN)
@@ -412,7 +410,7 @@ struct xrt_layer_data
 	 *
 	 * alignas for 32 bit client support,
 	 */
-	alignas(8) int64_t timestamp;
+	XRT_ALIGNAS(8) int64_t timestamp;
 
 	/*!
 	 * Composition flags
@@ -481,7 +479,7 @@ struct xrt_layer_data
 struct xrt_layer_frame_data
 {
 	//! alignas for 32 bit client support, see @ref ipc-design
-	alignas(8) int64_t frame_id;
+	XRT_ALIGNAS(8) int64_t frame_id;
 	int64_t display_time_ns;
 	enum xrt_blend_mode env_blend_mode;
 };
@@ -935,7 +933,7 @@ struct xrt_session_info
 {
 	bool is_overlay;
 	//! alignas for 32 bit client support, see @ref ipc-design
-	alignas(8) uint64_t flags;
+	XRT_ALIGNAS(8) uint64_t flags;
 	uint32_t z_order;
 };
 
@@ -953,7 +951,7 @@ struct xrt_compositor_info
 	 * Supported formats, never changes.
 	 * alignas for 32 bit client support, see @ref ipc-design
 	 */
-	alignas(8) int64_t formats[XRT_MAX_SWAPCHAIN_FORMATS];
+	XRT_ALIGNAS(8) int64_t formats[XRT_MAX_SWAPCHAIN_FORMATS];
 
 	//! Max texture size that GPU supports (size of a single dimension), zero means any size.
 	uint32_t max_texture_size;
diff --git a/src/xrt/include/xrt/xrt_device.h b/src/xrt/include/xrt/xrt_device.h
index 557796603..ee286b9ff 100644
--- a/src/xrt/include/xrt/xrt_device.h
+++ b/src/xrt/include/xrt/xrt_device.h
@@ -17,8 +17,6 @@
 #include "xrt/xrt_visibility_mask.h"
 #include "xrt/xrt_limits.h"
 
-#include <stdalign.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -167,7 +165,7 @@ struct xrt_input
 	bool active;
 
 	//! alignas for 32 bit client support, see @ref ipc-design
-	alignas(8) int64_t timestamp;
+	XRT_ALIGNAS(8) int64_t timestamp;
 
 	enum xrt_input_name name;
 
diff --git a/src/xrt/include/xrt/xrt_system.h b/src/xrt/include/xrt/xrt_system.h
index 995f71bc3..961a806f4 100644
--- a/src/xrt/include/xrt/xrt_system.h
+++ b/src/xrt/include/xrt/xrt_system.h
@@ -15,8 +15,6 @@
 #include "xrt/xrt_defines.h"
 #include "xrt/xrt_device.h"
 
-#include <stdalign.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -172,7 +170,7 @@ struct xrt_system_roles
 	 *
 	 * alignas for 32 bit client support, see @ref ipc-design
 	 */
-	alignas(8) uint64_t generation_id;
+	XRT_ALIGNAS(8) uint64_t generation_id;
 
 	/*!
 	 * Index in @ref xrt_system_devices::xdevs for the user's left