diff --git a/setup.cfg b/setup.cfg
index d30036c698..90317ec78a 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -61,3 +61,8 @@ convention = pep257
 # D202: Ignore a blank line after docstring (collision with Python Black in decorators)
 add-ignore = D104,D107,D202
 max-line-length = 120
+
+[tool:isort]
+known_first_party = pytorch_lightning,tests
+default_section=THIRDPARTY
+line_length=120