diff --git a/appveyor.yml b/appveyor.yml
index a0f2e4aa9..56a6a5972 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -28,6 +28,6 @@ build: off
 build_script:
   - cmd: mkdir %SRC_DIR%\build
   - cmd: cd %SRC_DIR%\build
-  - cmd: cmake %SRC_DIR% -G %CMAKE_GENERATOR% -DCMAKE_BUILD_TYPE=Release
+  - cmd: cmake %SRC_DIR% -G "%CMAKE_GENERATOR%" -DCMAKE_BUILD_TYPE=Release
   - cmd: if errorlevel 1 exit 1
   - cmd: cmake --build . --config Release --target netcdf