Dhoom 2: Back In Action (lang-hi??? ?, IPA-hnsd?md?m, also abbreviated and known as D:2, D2 and D2: Back In Action) is a 2006 Indian Bollywood action (action film) directed by Sanjay Gadhvi and produced by Aditya Chopra and Yash Chopra at an estimated budget of Rs (Indian rupee) 350 million. It is the second film in the Dhoom series (Dhoom series). Abhishek Bachchan and Uday Chopra star in the film as buddy cops Jai Dixit and Ali Akbar Fateh Khan, respectively. The duo attempt to capture Mr. Aryan (Hrithik Roshan), a professional thief whose passion is to steal rare and valuable collectibles using high-technology gadgets.

The film was shot primarily in India, Durban (Durban, South Africa), and Rio de Janeiro (Rio de Janeiro, Brazil), becoming the first major Hindi film (Hindi cinema) to be picturized in Brazil. The films distributor, Yash Raj Films, promoted the film by forging associations with Pepe Jeans and Coca-Cola. Indias biggest video game producing company, FXLabs, developed a game based on the film entitled Dhoom 2.5. The film premiered on 23 November 2006 in India, where it received the widest release in Indian cinema history with over 650 prints across the country.

Dhoom 2 was generally well-received by both critics and the mass audience. It became the highest grossing Indian film of 2006, fourth highest-grossing Bollywood film in India (List of highest-grossing Bollywood films#Highest-grossing Bollywood films in India, unadjusted for inflation) and the eighth highest-grossing Bollywood film in overseas markets (List of highest-grossing Bollywood films in overseas markets#Highest-grossing Bollywood films in Overseas markets, unadjusted for inflation). After grossing over Rs (Indian rupee) 1.34 billion (1000000000 (number)) (USD$ (US dollar)34 million), the film was elevated to a "blockbuster (blockbuster (entertainment))" rating on Box Office India. The film received 80% approval rating among critics on review aggregator Rotten Tomatoes.cite web title=Dhoom 2 url=date= work= publisher=Rotten Tomatoes accessdate=22 August 2009 Critics praised Dhoom 2 for its heavy action sequences. However, both Dhoom and Dhoom 2 inspired Indian youths to ride their motorcycles rashly, resulting in an increase in the number of road accidents in Mumbai, India and an appeal by the citys police commissioner to censor the fast-paced rash driving scenes in the film.