We report the case of a 13-year-old girl in whom an appendix carcinoid was found incidentally during excision of a choledochal cyst. Although incidental carcinoid tumors of the extrahepatic bile ducts have been reported, to the best of our knowledge this is the first published case of a choledochal cyst associated with an appendix carcinoid. We present this case to highlight the importance of conducting a thorough exploration of all quadrants of the abdomen before closure.