diff --git a/tox.ini b/tox.ini
index 347faf15c..6c216fd71 100644
--- a/tox.ini
+++ b/tox.ini
@@ -167,7 +167,9 @@ commands =
 
 [testenv:py37-freeze]
 changedir = testing/freeze
+# Disable PEP 517 with pip, which does not work with PyInstaller currently.
 deps =
+    --no-use-pep517
     pyinstaller
 commands =
     {envpython} create_executable.py