diff --git a/tox.ini b/tox.ini
index 30eb193dd3d..de1263fc47c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -53,6 +53,9 @@ commands_pre =
 deps =
     invoke
     requests
+    # Required, otherwise we interpret --no-binary :all: as
+    # "do not build wheels", which fails for PEP 517 requirements
+    pip>=19.3.1
 whitelist_externals = git
 commands =
     # Check that the vendoring is up-to-date