diff --git a/src/plugins/platformthemes/gtk3/CMakeLists.txt b/src/plugins/platformthemes/gtk3/CMakeLists.txt
index 6d3c7bf3a23..20487a6babe 100644
--- a/src/plugins/platformthemes/gtk3/CMakeLists.txt
+++ b/src/plugins/platformthemes/gtk3/CMakeLists.txt
@@ -15,6 +15,7 @@ qt_internal_add_plugin(QGtk3ThemePlugin
     OUTPUT_NAME qgtk3
     PLUGIN_TYPE platformthemes
     DEFAULT_IF FALSE
+    NO_UNITY_BUILD
     SOURCES
         main.cpp
         qgtk3dialoghelpers.cpp qgtk3dialoghelpers.h