How to Train Your Dragon is a 2010 American animated fantasy film loosely based on the 2003 novel by Cressida Cowell. Produced by DreamWorks Animation and distributed by Paramount Pictures, it was directed by Chris Sanders and Dean DeBlois, who co-wrote the screenplay with Will Davies, and produced by Bonnie Arnold. The film stars the voices of Jay Baruchel, Gerard Butler, Craig Ferguson, America Ferrera, Jonah Hill, Christopher Mintz-Plasse, T.J. Miller, and Kristen Wiig. The story takes place in Berk, a mythical Viking village; Hiccup, an undersized teen wishing to become a dragon slayer like the other Vikings, injures a rare Night Fury dragon but is unable to bring himself to kill it. He instead helps and befriends the dragon, and quickly discovers that things are not exactly as they seem in the conflict between Vikings and dragons.

In 2004, the book series began attracting the attention of the executives at DreamWorks Animation. After the success of Over the Hedge (2006), producer Bonnie Arnold shortly became interested in the newly acquired property. The directors of the film wanted to make sure to cash in the improvisation abilities of the secondary cast by frequently bringing them together in the recording sessions. The filmmakers hired cinematographer Roger Deakins (known for frequently collaborating with the Coen brothers) as a visual consultant to help them with lighting and aesthetic of the film and to add a live-action feel. John Powell composed the film's musical score.

How to Train Your Dragon premiered at the Gibson Amphitheater on March 21, 2010, and was released in the United States on March 26, by Paramount Pictures and DreamWorks Animation. The film was a critical and commercial success, grossing $494 million worldwide and becoming the tenth-highest-grossing film of 2010. It was widely acclaimed for its animation, voice acting, writing, musical score, humor, plot, and 3D sequences. The film was nominated for two awards at the 83rd Academy Awards and received numerous other accolades. How to Train Your Dragon is the first entry in what became the multimedia franchise of the same name, which includes two more films—How to Train Your Dragon 2 (2014) and How to Train Your Dragon: The Hidden World (2019). A live-action remake is scheduled to be released by Universal Pictures on June 13, 2025, with DeBlois returning to direct.