diff --git a/pkgs/development/python-modules/sympy/default.nix b/pkgs/development/python-modules/sympy/default.nix
index a05d13f466ee..a6c5d1fca425 100644
--- a/pkgs/development/python-modules/sympy/default.nix
+++ b/pkgs/development/python-modules/sympy/default.nix
@@ -27,10 +27,6 @@ buildPythonPackage rec {
   doCheck = false;
   pythonImportsCheck = [ "sympy" ];
 
-  preCheck = ''
-    export LANG="en_US.UTF-8"
-  '';
-
   passthru.tests = {
     inherit sage;
   };