Oh, Mr Porter! is a 1937 British comedy film starring Will Hay with Moore Marriott and Graham Moffatt and directed by Marcel Varnel. While not Hay's commercially most successful (although it grossed £500,000 at the box office – equal to about £34,000,000 at 2020 value), it is probably his best-known film to modern audiences. It is widely acclaimed as the best of Hay's work, and a classic of its genre. The film had its first public showing in November 1937 and went on general release on 3 January 1938.

The plot of Oh, Mr Porter was loosely based on the Arnold Ridley play The Ghost Train. The title was taken from Oh! Mr Porter, a music hall song.