Character mistake: On the day Rebecca arrives home, Junior Douglas says that he was "Valedictorian, Class of '95." Earlier, Drago talked of almost killing Running Buffalo "during that trouble back in the '40's," which would have been about 50 years earlier. That would mean Drago and McLintock were fighting Indians when they were babies, or possibly before they were born!
Character mistake: When Spencer Tracy is talking to his wife and daughter on two separate telephones, he places the phones up against each other so mom and daughter can talk to each other. One phone should be upside down so it would be speaker to transmitter rather than speaker to speaker.
Character mistake: When Audrey Hepburn confronts Carrie Grant by saying "Carson Dyle had no brother.", he would have definitely wondered how she came to know about this, and who is her hidden source of information. (01:16:00)