diff --git a/src/aedifix/config.py b/src/aedifix/config.py
index 2833fba..248c237 100644
--- a/src/aedifix/config.py
+++ b/src/aedifix/config.py
@@ -29,6 +29,7 @@ class ConfigFile(Configurable):
         "_cmake_configure_file",
         "_config_file_template",
         "_default_subst",
+        "_project_variables_file",
     )
 
     def __init__(
@@ -45,6 +46,13 @@ def __init__(
         """
         super().__init__(manager=manager)
         self._config_file_template = config_file_template.resolve()
+
+        config_file = self.template_file
+        if config_file.suffix == ".in":
+            # remove the trailing .in
+            config_file = config_file.with_suffix("")
+
+        self._project_variables_file = self.project_arch_dir / config_file.name
         self._default_subst = {"PYTHON_EXECUTABLE": sys.executable}
 
     @property
@@ -72,7 +80,7 @@ def project_variables_file(self) -> Path:
         The file is not guaranteed to exist, or be up to date. Usually it is
         created/refreshed during finalization of this object.
         """
-        return self.project_arch_dir / "gmakevariables"
+        return self._project_variables_file
 
     def _read_entire_cmake_cache(self, cmake_cache: Path) -> dict[str, str]:
         r"""Read a CMakeCache.txt and convert all of the cache values to
@@ -164,7 +172,7 @@ def finalize(self) -> None:
             If the user config file contains an unknown AEDIFIX substitution.
         """
         project_file = self.project_variables_file
-        template_file = self._config_file_template
+        template_file = self.template_file
         self.log(f"Using project file: {project_file}")
         self.log(f"Using template file: {template_file}")
 
diff --git a/tests/test_config.py b/tests/test_config.py
index 7f2d67a..9b68b6b 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -32,9 +32,29 @@ def test_create(self, manager: DummyManager, tmp_path: Path) -> None:
         assert config.template_file.exists()
         assert config.template_file.is_file()
         assert config.template_file == template
-
+        assert (
+            config.project_variables_file.name == template.with_suffix("").name
+        )
         assert config._default_subst == {"PYTHON_EXECUTABLE": sys.executable}
 
+    @pytest.mark.parametrize(
+        ("base", "expected"),
+        (
+            ("foo.bar.baz.in", "foo.bar.baz"),
+            ("foo.bar", "foo.bar"),
+            ("foo", "foo"),
+        ),
+    )
+    def test_project_variables_file(
+        self, manager: DummyManager, tmp_path: Path, base: str, expected: str
+    ) -> None:
+        template = tmp_path / base
+        template.touch()
+
+        config = ConfigFile(manager=manager, config_file_template=template)
+
+        assert config.project_variables_file.name == expected
+
 
 if __name__ == "__main__":
     sys.exit(pytest.main())