diff --git a/atst/app.py b/atst/app.py
index 46b017bb..b6832515 100644
--- a/atst/app.py
+++ b/atst/app.py
@@ -79,6 +79,10 @@ def make_config():
     config = ConfigParser()
     config.optionxform = str
 
+    config_files = [BASE_CONFIG_FILENAME, ENV_CONFIG_FILENAME]
+    if OVERRIDE_CONFIG_FILENAME:
+        config_files.append(OVERRIDE_CONFIG_FILENAME)
+
     config_files = [BASE_CONFIG_FILENAME, ENV_CONFIG_FILENAME]
     if OVERRIDE_CONFIG_FILENAME:
         config_files.append(OVERRIDE_CONFIG_FILENAME)