diff --git a/pkgs/development/python-modules/pyzmq/default.nix b/pkgs/development/python-modules/pyzmq/default.nix
index dcab96d12a6a..40273cce8887 100644
--- a/pkgs/development/python-modules/pyzmq/default.nix
+++ b/pkgs/development/python-modules/pyzmq/default.nix
@@ -32,4 +32,7 @@ buildPythonPackage rec {
       and not test_on_recv_wake \
       and not test_monitor"
   '';
+
+  # Some of the tests use localhost networking.
+  __darwinAllowLocalNetworking = true;
 }