diff --git a/pkgs/development/libraries/kde-frameworks/kimageformats.nix b/pkgs/development/libraries/kde-frameworks/kimageformats.nix
index d07bb36ea100..bc1b86099939 100644
--- a/pkgs/development/libraries/kde-frameworks/kimageformats.nix
+++ b/pkgs/development/libraries/kde-frameworks/kimageformats.nix
@@ -30,7 +30,6 @@ mkDerivation {
     qtbase
   ];
   outputs = [ "out" ]; # plugins only
-  CXXFLAGS = "-I${getDev ilmbase}/include/OpenEXR";
   cmakeFlags = [
     "-DKIMAGEFORMATS_HEIF=ON"
   ];