Thenali () is a 2000 Indian Tamil-language comedy film co-written and directed by K. S. Ravikumar. The film stars Kamal Haasan, Jayaram, Devayani and Jyothika, with Delhi Ganesh, Charle, Ramesh Khanna and Madhan Bob in supporting roles. It revolves around the title character who follows his psychiatrist Kailash on vacation to cure his numerous phobias. When Thenali becomes closer to Kailash's family, Kailash becomes increasingly obsessed with ridding him.

Thenali, inspired by the 1991 American film What About Bob?, is the first film produced by Ravikumar's company R. K. Celluloids, and the dialogues were written by Crazy Mohan. It was photographed by Priyan and edited by K. Thanikachalam, while the music was composed by A. R. Rahman. The film was shot predominantly in Ooty and Kodaikanal, while some song sequences were shot in New Zealand.

Thenali was released on 26 October 2000 to positive reviews and became a silver jubilee hit. The film won three Tamil Nadu State Film Awards, including a Special Jury award for Jayaram's performance, and Ravikumar won the Cinema Express Award for Best Director – Tamil.