diff --git a/pyspectral/config.py b/pyspectral/config.py
index b5e9dbf..0114641 100644
--- a/pyspectral/config.py
+++ b/pyspectral/config.py
@@ -82,4 +82,4 @@ def _get_env_or_builtin_config_path() -> Path:
                       f"'PSP_CONFIG_FILE' is not a file or does not exist!")
     if config_file is None:
         return BUILTIN_CONFIG_FILE
-    return config_file
+    return Path(config_file)