Doctor is a 2021 Indian Tamil-language action comedy film written and directed by Nelson Dilipkumar. It is produced by Sivakarthikeyan under Sivakarthikeyan Productions, in the company of KJR Studios. The film stars Sivakarthikeyan, Vinay Rai and Priyanka Mohan (in her Tamil debut), with Archana Chandhoke, Yogi Babu, Milind Soman, Redin Kingsley, Deepa Shankar, Sunil Reddy and Shiva Aravind. It follows a military doctor, who seeks to rescue his ex-fiancée's niece from a child trafficker.

The film was officially announced in December 2019. Principal photography commenced the same month and wrapped by early-January 2021. It was shot in Chennai and Goa. The film has music composed by Anirudh Ravichander, cinematography handled by Vijay Kartik Kannan and editing by R. Nirmal.

Doctor was released in theatres on 9 October 2021, following multiple delays related to the COVID-19 pandemic. It received positive reviews from critics, grossed over ₹100 crore and became a commercial success at the box office. A sequel was announced in 2023.