diff --git a/dodgy/run.py b/dodgy/run.py
index 9a7e62e..55fb332 100644
--- a/dodgy/run.py
+++ b/dodgy/run.py
@@ -10,6 +10,8 @@
     r'(^|%(sep)s)\.[^\.]',   # ignores any files or directories starting with '.'
     r'^tests?%(sep)s?',
     r'%(sep)stests?(%(sep)s|$)',
+    # Ignore foo_test(s)/.
+    r'_tests?(%(sep)s|$)',
 )]