diff --git a/pkgs/development/python-modules/pytest-xdist/default.nix b/pkgs/development/python-modules/pytest-xdist/default.nix
index fa1b0f63fabcd..b17b6f2f763a6 100644
--- a/pkgs/development/python-modules/pytest-xdist/default.nix
+++ b/pkgs/development/python-modules/pytest-xdist/default.nix
@@ -9,6 +9,7 @@
 , pytest
 , pytest-forked
 , psutil
+, pexpect
 }:
 
 buildPythonPackage rec {
@@ -25,9 +26,15 @@ buildPythonPackage rec {
   buildInputs = [
     pytest
   ];
-  checkInputs = [ pytestCheckHook filelock ];
+  checkInputs = [ pytestCheckHook filelock pexpect ];
   propagatedBuildInputs = [ execnet pytest-forked psutil ];
 
+  pytestFlagsArray = [
+    # pytest can already use xdist at this point
+    "--numprocesses=$NIX_BUILD_CORES"
+    "--forked"
+  ];
+
   # access file system
   disabledTests = [
     "test_distribution_rsyncdirs_example"
@@ -40,6 +47,8 @@ buildPythonPackage rec {
     "test_internal_errors_propagate_to_controller"
   ];
 
+  setupHook = ./setup-hook.sh;
+
   meta = with lib; {
     description = "Pytest xdist plugin for distributed testing and loop-on-failing modes";
     homepage = "https://github.com/pytest-dev/pytest-xdist";
diff --git a/pkgs/development/python-modules/pytest-xdist/setup-hook.sh b/pkgs/development/python-modules/pytest-xdist/setup-hook.sh
new file mode 100644
index 0000000000000..8bba79ca3360e
--- /dev/null
+++ b/pkgs/development/python-modules/pytest-xdist/setup-hook.sh
@@ -0,0 +1,7 @@
+pytestXdistHook() {
+    pytestFlagsArray+=("--numprocesses=$NIX_BUILD_CORES" "--forked" )
+}
+
+if [ -z "${dontUsePytestXdist-}" ] && [ -z "${dontUsePytestCheck-}" ]; then
+    addEnvHooks "$hostOffset" pytestXdistHook
+fi