Dhoom 2 (trans. Blast 2), also known as Dhoom 2: Back in Action and stylized as Dhoom: 2, is a 2006 Indian Hindi-language heist action thriller film directed by Sanjay Gadhvi and written by Vijay Krishna Acharya, based on a story by producer Aditya Chopra, who backed the film at an estimated budget of ₹350 million under the banner Yash Raj Films. The film stars Abhishek Bachchan, Hrithik Roshan, Aishwarya Rai, Bipasha Basu and Uday Chopra. Dhoom 2 was shot primarily in India, Durban and Rio de Janeiro, becoming the first major Hindi film to be shot in Brazil. It is a sequel to the 2004 film Dhoom and is the second installment in the Dhoom series. Abhishek Bachchan and Uday Chopra reprise their roles as buddy cops Jai Dixit and Ali Khan, respectively. Yash Raj Films also collaborated with Pepe Jeans and Coca-Cola for the film's promotional tie-ups.

Dhoom 2 premiered on 24 November 2006 in India, where it received the widest release in Indian cinema history with over 1800 prints, and grossed over ₹1.5 billion, and was declared a "blockbuster" by Box Office India. It became the highest grossing Hindi film of 2006 and was the highest-grossing Hindi film of all time as well at the time of its release. It also is the seventh highest-grossing Bollywood film in overseas markets. It received positive reviews from critics upon release, with praise for its action sequences, soundtrack, cinematography and cast performances (particularly Roshan), but criticism directed towards its pacing and writing.

At the 52nd Filmfare Awards, Dhoom 2 received 8 nominations, including Best Film, Best Director (Gadhvi) and Best Actress (Rai), and won Best Actor (Roshan).

The film also proved to be controversial post release, as there was an appeal by the Mumbai city police commissioner to censor the fast-paced rash driving scenes due to fears that it would inspire Indian youths to ride their motorcycles rashly, resulting in an increase in the number of road accidents. A sequel titled Dhoom 3 was released on 20 December 2013, which also went on to become the twelfth-highest-grossing Hindi film to date, and the highest-grossing Hindi film of all time as well at the time of its release.