diff --git a/pkgs/development/python-modules/scipy/default.nix b/pkgs/development/python-modules/scipy/default.nix
index aa578d21d257..e791454b9018 100644
--- a/pkgs/development/python-modules/scipy/default.nix
+++ b/pkgs/development/python-modules/scipy/default.nix
@@ -54,6 +54,7 @@ buildPythonPackage rec {
   checkPhase = ''
     runHook preCheck
     pushd "$out"
+    export OMP_NUM_THREADS=$(( $NIX_BUILD_CORES / 4 ))
     ${python.interpreter} -c "import scipy; scipy.test('fast', verbose=10, parallel=$NIX_BUILD_CORES)"
     popd
     runHook postCheck