diff --git a/src/main_x11.cpp b/src/main_x11.cpp
index bb722bf5d8..66e0341f1c 100644
--- a/src/main_x11.cpp
+++ b/src/main_x11.cpp
@@ -362,6 +362,8 @@ int main(int argc, char *argv[])
 
     KWin::ApplicationX11 a(argc, argv);
     a.setupTranslator();
+    // reset QT_QPA_PLATFORM so we don't propagate it to our children (e.g. apps launched from the overview effect)
+    qunsetenv("QT_QPA_PLATFORM");
 
     KSignalHandler::self()->watchSignal(SIGTERM);
     KSignalHandler::self()->watchSignal(SIGINT);