Continuity mistake: In the scene with the lovely dancing ladies, Cotten blows cigar smoke just before a cut to him from the opposite angle. From this angle there is no smoke. This takes place just before Wells throws his jacket to Cotten.
Continuity mistake: Kasper Gutman goes wild cutting the Maltese Falcon continuously with his knife, but in one of the inserted close-ups of him he's just standing there not doing anything. (01:28:40)
Continuity mistake: When Johnnie and Lina arrive back from their honeymoon, they decide to have tea and cake in their new home. Johnnie picks up the tea pot and starts to pour the tea, but then he picks up the tea pot for a second time and starts again to pour the tea.
Continuity mistake: Chuck and Ferdie are among six people who a driver drops off at an abandoned lodge. In the long shots of the lodge, rain is falling at a very sharp angle but in the close-ups the rain is coming straight down.