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 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.

Realizing the dragons have been forced to attack Berk to survive, Astrid wishes to tell the village, but Hiccup advises against it to protect Toothless.

Stoick and his Vikings locate and break open the dragon's nest, awakening the Red Death, which easily overwhelms them.

She kept focusing on the project as time went on, and when DreamWorks Animation co-president of production Bill Damaschke asked her what she wanted to work on next, she chose "How to Train Your Dragon".

[9] Damaschke hired Chris Sanders to take over, who in turn called Dean DeBlois, with whom he had worked on Lilo & Stitch, to co-direct.

[9] The original plot has been described by DeBlois as "heavily loyal to the book," but was regarded as being too "sweet" and "whimsical" and geared to a younger demographic.

The filmmakers hired cinematographer Roger Deakins (known for frequently collaborating with the Coen brothers) as a visual consultant to help them with lighting and overall look of the film and to "add a live-action feel".

Toothless in particular tried to combine various dragon traits in a black panther-inspired design, that also had large ears and eyes to convey emotion better.

[11] The directors made sure to cash in on the improvisation abilities of the secondary cast—Christopher Mintz-Plasse, Jonah Hill, Kristen Wiig and T.J Miller—by frequently bringing them together in the recording sessions.

Powell composed an orchestral score, combining bombastic brass with loud percussion and soothing strings, while also using exotic Scottish and Irish tones with instruments like the penny whistle and bagpipes.

Powell earned his first Academy Award nomination for his work on the film, ultimately losing to Trent Reznor and Atticus Ross for their score for The Social Network.

[15] Entertainment reporter Kim Masters described the 3D release schedule around March 2010 as a "traffic jam", and speculated that the lack of 3D screen availability could hurt Katzenberg's prospects despite his support of the 3D format.

Among the features available in the two-disc DVD edition and Blu-ray is an original sequel short film, Legend of the Boneknapper Dragon.

[19] In July 2014, the film's distribution rights were purchased by DreamWorks Animation from Paramount Pictures and transferred to 20th Century Fox[20] before reverting to Universal Studios in 2018.

[27] The website's critical consensus states, "Boasting dazzling animation, a script with surprising dramatic depth, and thrilling 3-D sequences, How to Train Your Dragon soars.

[30] Matt Risley of Variety wrote a highly positive review, hailing it as "undoubtedly Dreamworks' best film yet, and quite probably the best dragon movie ever made".

[31] James Berardinelli of ReelViews gave it 3.5 out of 4 stars, and complimented both the "technically proficient" animation and the "witty, intelligent, surprisingly insightful script".

[32] Claudia Puig of USA Today noted that the film had "surprising depth", and praised the "sweetly poignant tale of friendship between man and animal".

[34] Both Roger Ebert of The Chicago Sun-Times and A. O. Scott of At The Movies felt that character and story development had been sidelined in favour of the visual spectacle.

Ebert criticised the lengthy "aerial battles between tamed dragons and evil ones", but did note that "[the film] is bright, good-looking, and has high energy".

Jay Baruchel, America Ferrera, Christopher Mintz-Plasse, and T. J. Miller reprise their roles as Hiccup, Astrid, Fishlegs, and Tuffnut.