diff --git a/setup.py b/setup.py
index 4bc2fea0..d627c5b2 100644
--- a/setup.py
+++ b/setup.py
@@ -107,7 +107,7 @@ def build_extension(self, ext):
         build_args = ['--config', cfg]
 
         if platform.system() == "Windows":
-            cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir), "-G", "ninja"]
+            cmake_args += ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY_{}={}'.format(cfg.upper(), extdir), "-G", "Ninja"]
             if sys.maxsize > 2**32:
                 cmake_args += ['-A', 'x64']
             build_args += ['--', '/m']