diff --git a/.isort.cfg b/.isort.cfg
index d535851..0fadb83 100644
--- a/.isort.cfg
+++ b/.isort.cfg
@@ -8,6 +8,7 @@ known_third_party =
     requests,
     simplejson
     six,
+    sphinx,
     stix2patterns,
     taxii2client,
 known_first_party = stix2