diff --git a/pkgs/development/libraries/qt-6/modules/qtbase.nix b/pkgs/development/libraries/qt-6/modules/qtbase.nix
index a14028e1259a..87a4a013e917 100644
--- a/pkgs/development/libraries/qt-6/modules/qtbase.nix
+++ b/pkgs/development/libraries/qt-6/modules/qtbase.nix
@@ -250,7 +250,10 @@ stdenv.mkDerivation rec {
     "-framework GSS"
   ]);
 
-  env.NIX_CFLAGS_COMPILE = "-DNIXPKGS_QT_PLUGIN_PREFIX=\"${qtPluginPrefix}\"";
+  env.NIX_CFLAGS_COMPILE = "-DNIXPKGS_QT_PLUGIN_PREFIX=\"${qtPluginPrefix}\""
+    # These flags are in glib-2.0.pc but somehow don't get applied automatically.
+    + lib.optionalString (!stdenv.hostPlatform.isMinGW)
+      " -I${glib.dev}/include/glib-2.0 -I${glib.out}/lib/glib-2.0/include";
 
   outputs = [ "out" "dev" ];