diff --git a/pkgs/development/python-modules/sphinx/default.nix b/pkgs/development/python-modules/sphinx/default.nix
index 5a27f04bd0ee..5edfaa251515 100644
--- a/pkgs/development/python-modules/sphinx/default.nix
+++ b/pkgs/development/python-modules/sphinx/default.nix
@@ -95,6 +95,9 @@ buildPythonPackage rec {
 
   preCheck = ''
     export HOME=$(mktemp -d)
+
+    # Unset dummy cert file path set in stdenv, that confuses certifi
+    unset NIX_SSL_CERT_FILE
   '';
 
   disabledTests = [