diff --git a/lib/spack/spack/build_systems/cmake.py b/lib/spack/spack/build_systems/cmake.py
index 7fff3771e9b..3b3b61f1153 100644
--- a/lib/spack/spack/build_systems/cmake.py
+++ b/lib/spack/spack/build_systems/cmake.py
@@ -248,7 +248,8 @@ def std_cmake_args(self):
     @staticmethod
     def std_args(pkg, generator=None):
         """Computes the standard cmake arguments for a generic package"""
-        generator = generator or "Unix Makefiles"
+        default_generator = "Ninja" if sys.platform == "win32" else "Unix Makefiles"
+        generator = generator or default_generator
         valid_primary_generators = ["Unix Makefiles", "Ninja"]
         primary_generator = _extract_primary_generator(generator)
         if primary_generator not in valid_primary_generators:
diff --git a/lib/spack/spack/test/build_systems.py b/lib/spack/spack/test/build_systems.py
index 54ed485f250..79cea99eeba 100644
--- a/lib/spack/spack/test/build_systems.py
+++ b/lib/spack/spack/test/build_systems.py
@@ -23,8 +23,6 @@
 
 DATA_PATH = os.path.join(spack.paths.test_path, "data")
 
-pytestmark = pytest.mark.skipif(sys.platform == "win32", reason="does not run on windows")
-
 
 @pytest.fixture()
 def concretize_and_setup(default_mock_concretization):
@@ -45,6 +43,7 @@ def _func(dir_str):
     return _func
 
 
+@pytest.mark.skipif(sys.platform == "win32", reason="make not available on Windows")
 @pytest.mark.usefixtures("config", "mock_packages", "working_env")
 class TestTargets:
     @pytest.mark.parametrize(
@@ -93,6 +92,7 @@ def test_negative_ninja_check(self, input_dir, test_dir, concretize_and_setup):
             s.package._if_ninja_target_execute("check")
 
 
+@pytest.mark.skipif(sys.platform == "win32", reason="autotools not available on windows")
 @pytest.mark.usefixtures("config", "mock_packages")
 class TestAutotoolsPackage:
     def test_with_or_without(self, default_mock_concretization):