3 Idiots is a 2009 Indian Hindi-language coming-of-age comedy-drama film written, edited and directed by Rajkumar Hirani, co-written by Abhijat Joshi and produced by Vidhu Vinod Chopra. The film stars Aamir Khan, R. Madhavan and Sharman Joshi in the titular roles, marking their reunion three years after Rang De Basanti (2006), while Kareena Kapoor, Boman Irani and Omi Vaidya appear in pivotal roles. Narrated through two parallel dramas, one in the present and the other set ten years in the past, the story follows the friendship of three students at an Indian engineering college and is a satire about the intrinsic paternalism under the Indian education system.

Adapted loosely from Chetan Bhagat's novel Five Point Someone, It is produced by Chopra under the banner Vinod Chopra Films, 3 Idiots incorporated real Indian inventions created by Remya Jose, Mohammad Idris, Jahangir Painter and Sonam Wangchuk, the latter of whom also inspired Khan's character.

Upon its release on 25 December 2009, 3 Idiots received widespread critical acclaim with praise directed towards its direction, themes, humour, story, screenplay, soundtrack and performances of the cast and was a commercial success. It was also the highest-grossing film in its opening weekend in India, had the highest opening day collections for an Indian film up until that point, and also held the record for the highest net collections in the first week for a Hindi film. Eventually, it became one of the few Indian films at the time to become successful in East Asian markets such as China and Japan, eventually bringing its worldwide gross to ₹460 crore ($90 million) — it was the highest-grossing Indian film ever at the time until 2013 and the highest grossing Indian film of the 2000s.

At the 57th National Film Awards, 3 Idiots won 3 National Film Awards, including Best Popular Film Providing Wholesome Entertainment. Additionally, the film received 11 nominations at the 55th Filmfare Awards, including Best Actor (Khan), Best Actress (Kapoor) and Best Supporting Actor (Madhavan and Joshi), and won a leading 6 awards (tying with Dev.D), including Best Film, Best Director (Hirani) and Best Supporting Actor (Irani). Overseas, it won the Grand Prize at Japan's Videoyasan Awards, while it was nominated for Best Outstanding Foreign Language Film at the Japan Academy Awards and Best Foreign Film at China's Beijing International Film Festival.

3 Idiots is now considered to be among the greatest Indian films ever made. The film also had a social impact on attitudes toward education in India, as well as in other Asian countries such as China and South Korea. It was remade in Tamil as Nanban (2012), which also received critical praise and commercial success. A Mexican remake, 3 Idiotas, was also released in 2017.