diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index b425c971033..ab18ed507e4 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -951,12 +951,6 @@ def set(path: str, value: Any, scope: Optional[str] = None) -> None:
     return CONFIG.set(path, value, scope)
 
 
-def add_default_platform_scope(platform: str) -> None:
-    plat_name = os.path.join("defaults", platform)
-    plat_path = os.path.join(CONFIGURATION_DEFAULTS_PATH[1], platform)
-    CONFIG.push_scope(DirectoryConfigScope(plat_name, plat_path))
-
-
 def scopes() -> Dict[str, ConfigScope]:
     """Convenience function to get list of configuration scopes."""
     return CONFIG.scopes
diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index e1d445f5a1c..39c13b8e6a5 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -635,11 +635,6 @@ def ensure_debug(monkeypatch):
     tty.set_debug(current_debug_level)
 
 
-@pytest.fixture(autouse=sys.platform == "win32", scope="session")
-def platform_config():
-    spack.config.add_default_platform_scope(spack.platforms.real_host().name)
-
-
 @pytest.fixture
 def default_config():
     """Isolates the default configuration from the user configs.