diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 25c576391744..2e1b4e23ca5e 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -17407,7 +17407,7 @@ in modules // {
 
     preConfigure = ''
       export LDFLAGS="-L${pkgs.fftw.out}/lib -L${pkgs.fftwFloat.out}/lib -L${pkgs.fftwLongDouble.out}/lib"
-      export CFLAGS="-I${pkgs.fftw.dev}/include -I${pkgs.fftwFloat}/include -I${pkgs.fftwLongDouble}/include"
+      export CFLAGS="-I${pkgs.fftw.dev}/include -I${pkgs.fftwFloat.dev}/include -I${pkgs.fftwLongDouble}/include"
     '';
     #+ optionalString isDarwin ''
     #  export DYLD_LIBRARY_PATH="${pkgs.fftw.out}/lib"