Moria says, "An American Werewolf in London was innovative at what it did during its day, although I fall short of calling it the all-time great genre classic that many were certain it was at the time." 1000 Misspent Hours says, "It’s extremely witty, surprisingly well acted ..., and tautly directed" and closes with this: "The long and short of it is: watch this movie. Director John Landis really knew what he was doing here". Empire Online gives it 4 out of 5 stars and concludes, "Carnivorous lunar activities rarely come any more entertaining than this."
Roger Ebert says, "it's as if John Landis thought the technology would be enough. We never get a real feeling for the characters, we never really believe the places ...), and we are particularly disappointed by the ending." Rotten Tomatoes has a critics score of 89%.