Lang considered M to be his favorite of his own films because of the social criticism in the film. In 1937, he told a reporter that he made the film "to warn mothers about neglecting children".
A Hollywood remake of the same name was released in 1951, shifting the action from Berlin to Los Angeles. Nero Films head Seymour Nebenzal and his son Harold produced the film for Columbia Pictures. Lang had once told a reporter "People ask me why I do not remake M in English. I have no reason to do that. I said all I had to say about that subject in the picture. Now I have other things to say." The remake was directed by Joseph Losey and starred David Wayne in Lorre's role. Losey stated that he had seen M in the early 1930s and watched it again shortly before shooting the remake, but that he "never referred to it. I only consciously repeated one shot. There may have been unconscious repetitions in terms of the atmosphere, of certain sequences." Lang later said that when the remake was released he "had the best reviews of my life".
The original 1931 M was ranked at number thirty-three in Empire magazines' "The 100 Best Films Of World Cinema" in 2010.
In 2003, M was adapted for radio by Peter Straughan and broadcast on BBC Radio 3 on February 2, later re-broadcast on BBC Radio 4 Extra on 8 October 2016. Directed by Toby Swift, this drama won the Prix Italia for Adapted Drama in 2004.