diff --git a/qt_cmdline.cmake b/qt_cmdline.cmake
index 0347f86eefa..a30031135db 100644
--- a/qt_cmdline.cmake
+++ b/qt_cmdline.cmake
@@ -141,7 +141,10 @@ function(qt_commandline_cxxstd arg val nextok)
         qtConfAddError("Missing argument to command line parameter '${arg}'.")
         return()
     endif()
-    if(val MATCHES "(c\\+\\+)?(20|2a)")
+    if(val MATCHES "(c\\+\\+)?(17|1z)")
+        qtConfCommandlineDisableFeature(c++20)
+        qtConfCommandlineDisableFeature(c++2b)
+    elseif(val MATCHES "(c\\+\\+)?(20|2a)")
         qtConfCommandlineEnableFeature(c++20)
         qtConfCommandlineDisableFeature(c++2b)
     elseif(val MATCHES "(c\\+\\+)?(2b)")