diff --git a/pkgs/by-name/bi/bison/package.nix b/pkgs/by-name/bi/bison/package.nix
index d1c015601320..6b5fbd750de3 100644
--- a/pkgs/by-name/bi/bison/package.nix
+++ b/pkgs/by-name/bi/bison/package.nix
@@ -41,6 +41,8 @@ stdenv.mkDerivation rec {
   propagatedBuildInputs = [ m4 ];
 
   enableParallelBuilding = true;
+  # tests are flaky / timing sensitive on FreeBSD
+  enableParallelChecking = !stdenv.hostPlatform.isFreeBSD;
 
   # Normal check and install check largely execute the same test suite
   doCheck = false;