Howl's Moving Castle (Japanese: ハウルの動く城, Hepburn: Hauru no Ugoku Shiro) is a 2004 Japanese animated fantasy film written and directed by Hayao Miyazaki. It is loosely based on the 1986 novel by English author Diana Wynne Jones. The film was produced by Toshio Suzuki, animated by Studio Ghibli, and distributed by Toho. The Japanese voice cast featured Chieko Baisho and Takuya Kimura, while the English dub version starred Jean Simmons, Emily Mortimer, Lauren Bacall, Christian Bale, Josh Hutcherson and Billy Crystal. The film is set in a fictional kingdom where both magic and early twentieth-century technology are prevalent, against the backdrop of a war with another kingdom. It tells the story of Sophie, a young milliner who is turned into an elderly woman by a witch who enters her shop and curses her. She encounters a wizard named Howl and gets caught up in his resistance to fighting for the king.

Influenced by Miyazaki's opposition to the United States' invasion of Iraq in 2003, the film contains strong anti-war themes. Miyazaki stated that he "had a great deal of rage" about the Iraq war, which led him to make a film that he felt would be poorly received in the United States. It also explores the theme of old age, depicting age positively as something that grants the protagonist freedom. The film contains feminist elements as well and carries messages about the value of compassion. The film is significantly thematically different from the novel; while the novel focuses on challenging class and gender norms, the film focuses on love, personal loyalty, and the destructive effects of war.

Howl's Moving Castle premiered at the 61st Venice International Film Festival on 5 September 2004, and was theatrically released in Japan on 20 November 2004. It went on to gross $190 million in Japan and $236 million worldwide, making it one of the most commercially successful Japanese films in history. The film received critical acclaim, with particular praise for its visuals and Miyazaki's presentation of the themes. It was nominated for the Academy Award for Best Animated Feature at the 78th Academy Awards, but lost to Wallace & Gromit: The Curse of the Were-Rabbit. It won several other awards, including four Tokyo Anime Awards and a Nebula Award for Best Script.