diff --git a/pkgs/applications/science/electronics/flopoco/default.nix b/pkgs/applications/science/electronics/flopoco/default.nix
index cf0ebf18ff75..e15ef3277a66 100644
--- a/pkgs/applications/science/electronics/flopoco/default.nix
+++ b/pkgs/applications/science/electronics/flopoco/default.nix
@@ -54,12 +54,12 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [
     bison
     cmake
+    flex
     installShellFiles
   ];
 
   buildInputs = [
     boost
-    flex
     gmp
     libxml2
     mpfi