Athadu (transl. He) is a 2005 Indian Telugu-language action thriller film written and directed by Trivikram Srinivas and produced by Jayabheri Arts. The film stars Mahesh Babu, alongside Trisha, Sonu Sood, Prakash Raj, Nassar, Sunil, Sayaji Shinde, Kota Srinivasa Rao and Brahmanandam. The music was composed by Mani Sharma, while the cinematography and editing were handled by K. V. Guhan and Sreekar Prasad. The film follows a professional killer, hired to stage the assassination of a politician, who finds himself framed for the actual murder, leading him to assume a dead man's identity to escape the law.

Athadu received positive reviews from critics and audiences, and it went on to become one of the highest grossing Telugu films of all time. The film received several accolades including three Nandi Awards and a Filmfare Award South for Best Director – Telugu. Athadu is widely considered to be a modern classic of Telugu cinema. It holds the record of being the most telecasted Telugu film with over 1,000 times on television.

It was remade in Hindi in 2009 as Ek: The Power of One.