Mundhanai Mudichu (transl. Saree Knot) is a 1983 Indian Tamil-language romantic comedy film directed and written by K. Bhagyaraj, who also stars alongside Urvashi. The film focuses on Parimala, a mischievous village girl, who falls in love with a widower who works as a teacher in the village. She marries him by falsely accusing him of having sex with her, but she has to take drastic steps to win his love.

Bhagyaraj based the story of Mundhanai Mudichu on his friend who lost his wife, and a woman who fell in love with him even as others started gossiping about them. Another inspiration was a poster of Ramu (1966) which depicted its protagonist as a single father, and Bhagyaraj imagining himself in that position. The film was produced by AVM Productions, photographed by Ashok Kumar and edited by A. Selvanathan. It was the first Tamil film for Urvashi.

Mundhanai Mudichu was released on 22 July 1983 and became a major box office success, netting ₹40 million against a budget of ₹3 million and running for over 25 weeks in theatres, thus becoming a silver jubilee film. It won the Cinema Express Award for Best Film – Tamil, and Bhagyaraj won the Filmfare Award for Best Actor – Tamil. The film was remade in Telugu as Moodu Mullu (1983), in Hindi as Masterji (1985) and in Kannada as Halli Meshtru (1992).