diff --git a/pkgs/development/python-modules/pybind11/default.nix b/pkgs/development/python-modules/pybind11/default.nix
index 241953cda3ed..e97db8beefe0 100644
--- a/pkgs/development/python-modules/pybind11/default.nix
+++ b/pkgs/development/python-modules/pybind11/default.nix
@@ -1,6 +1,7 @@
 { stdenv
 , lib
 , buildPythonPackage
+, pythonOlder
 , fetchFromGitHub
 , cmake
 , boost
@@ -9,6 +10,7 @@
 , catch
 , numpy
 , pytestCheckHook
+, libxcrypt
 }:
 
 buildPythonPackage rec {
@@ -27,6 +29,7 @@ buildPythonPackage rec {
   '';
 
   nativeBuildInputs = [ cmake ];
+  buildInputs = lib.optionals (pythonOlder "3.9") [ libxcrypt ];
 
   dontUseCmakeBuildDir = true;