Pokémon: Mewtwo Returns, released in Japan as Pocket Monsters: Mewtwo! Ware wa Koko ni Ari: MEWTWO SAGA (ポケットモンスター ミュウツー! 我ハココニ在リ MEWTWO SAGA, Poketto Monsutā: Myuutsū! Ware wa Koko ni Ari MEWTWO SAGA, "Pocket Monsters: Mewtwo! I Am Here 'MEWTWO SAGA'"), is a special episode of the Pokémon anime series and a direct sequel to Pokémon: The First Movie (1998). It was first broadcast in Japan on December 30, 2000 and was released on VHS and DVD in Japan on March 21, 2001. It went direct-to-video in Australia on August 17, 2001, then in the United States and Canada on December 4, 2001, and in the UK on February 11, 2002.

In the American dubbed version, the DVD (but not the VHS) features a second mini-feature in addition to the movie feature named The Uncut Story of Mewtwo's Origin. This 10-minute segment was originally part of Mewtwo Strikes Back's running length in the Japanese version, but it was cut from the U.S. release of that movie because it was deemed too dark and morose for the film's American "G" rating. The German DVD release also includes the English language track.

The Japanese opening song is "OK！" by Rica Matsumoto. The ending song is "To My Best Best Friend" (ぼくのベストフレンドへ, Boku no Besuto Furendo e) by Hiromi Iwasaki, and the English opening song is "Born to Be a Winner" by David Ralfe.