diff --git a/src/microsoft/vulkan/meson.build b/src/microsoft/vulkan/meson.build
index c6ed8b9f6b7..7e4cbb5ce99 100644
--- a/src/microsoft/vulkan/meson.build
+++ b/src/microsoft/vulkan/meson.build
@@ -44,7 +44,6 @@ dzn_flags = [ ]
 dzn_cpp_flags = [ ]
 
 if with_platform_windows
-  dzn_flags += '-DVK_USE_PLATFORM_WIN32_KHR'
   libdzn_files += files('dzn_dxgi.c')
 endif