diff --git a/meson.build b/meson.build
index 61eb1fef01..17737c536b 100644
--- a/meson.build
+++ b/meson.build
@@ -2300,7 +2300,7 @@ if vulkan.found()
   if not libglslang.found()
     # FIXME: Get spirv-tools to enable opt.
     glslang_opts = cmake.subproject_options()
-    glslang_opts.add_cmake_defines({'ENABLE_OPT': false})
+    glslang_opts.add_cmake_defines({'ENABLE_OPT': false, 'ENABLE_HLSL': false})
     glslang_subpro = cmake.subproject('glslang', options: glslang_opts)
     libglslang = declare_dependency(link_with: [
           glslang_subpro.target('glslang'),