Black Sheep Boy Appendix is the fourth EP by indie band Okkervil River, released on November 22, 2005. This mini-album is a continuation of their 2005 release, Black Sheep Boy and is a compilation of unfinished and reworked songs from that album. The disc also includes "Another Radio Song," a re-recorded and lyrically altered version of "For the Captain," a song featured on the band's 1999 debut release, Stars Too Small to Use. "Black Sheep Boy #4" is a re-recorded and lyrically altered version of "Disfigured Cowboy," originally released on the Comes With a Smile issue #11 CD sampler, and was played on an episode ("One Night") of Cold Case.
The definitive double-disc CD version contains a video for "No Key No Plan," directed by Will Sheff.