Other: In the scene where Brad Pitt and Casey Affleck are sitting in Jesse's house, right before Casey kills him, Jesse's wife yells out from the kitchen to them that breakfast is ready. You can see Brad Pitt is mouthing her line.

Continuity: While Dick Liddle is talking to Robert Ford, Ford's hair is curled to his left, yet in one shot during the sequence, Ford's hair is straight, then goes back to being curled the rest of the sequence.

Continuity: During the conversation between Jesse James and Charley Ford after James has killed Ed Miller and woke Charley in the middle of the night, Charley's right suspender is initially twisted, yet, in the next shot his suspender is flat against his body, and remains so for the rest of the sequence.

Factual error: At the beginning of the movie, in the conversation betwenn Frank James and Robert Ford, the term "gunslinger" is used a few times. However, the term "gunslinger" didn't come into use until the 1920s (the movie is set in the 1880s).