diff --git a/IPython/external/qt_loaders.py b/IPython/external/qt_loaders.py
index 2e822e2..ef6b898 100644
--- a/IPython/external/qt_loaders.py
+++ b/IPython/external/qt_loaders.py
@@ -68,7 +68,7 @@ def commit_api(api):
         ID.forbid('PySide')
         ID.forbid('PyQt4')
         ID.forbid('PyQt5')
-    if api == QT_API_PYSIDE:
+    elif api == QT_API_PYSIDE:
         ID.forbid('PySide2')
         ID.forbid('PyQt4')
         ID.forbid('PyQt5')