diff --git a/pkgs/development/python-modules/rx/default.nix b/pkgs/development/python-modules/rx/default.nix
index 6945d7486f66..7f8ba49e0274 100644
--- a/pkgs/development/python-modules/rx/default.nix
+++ b/pkgs/development/python-modules/rx/default.nix
@@ -14,6 +14,11 @@ buildPythonPackage rec {
 
   checkInputs = [ nose ];
 
+  # Some tests are nondeterministic. (`grep sleep -r tests`)
+  # test_timeout_schedule_action_cancel: https://hydra.nixos.org/build/74954646
+  # test_new_thread_scheduler_timeout: https://hydra.nixos.org/build/74949851
+  doCheck = false;
+
   meta = {
     homepage = https://github.com/ReactiveX/RxPY;
     description = "Reactive Extensions for Python";