diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index c25795399c5..a8e100883cb 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -5380,7 +5380,9 @@ in {
   protobuf = callPackage ../development/python-modules/protobuf {
     disabled = isPyPy;
     doCheck = !isPy3k;
-    protobuf = pkgs.protobuf3_12;
+    # If a protobuf upgrade causes many Python packages to fail, please pin it
+    # here to the previous version.
+    protobuf = pkgs.protobuf;
   };
 
   psd-tools = callPackage ../development/python-modules/psd-tools { };