Unnal Mudiyum Thambi is a 1988 Indian Tamil-language musical-drama film written and directed by K. Balachander. Produced by Kavithalayaa Productions, the film stars Kamal Haasan, Gemini Ganesan, and Seetha. Janagaraj, Prasad Babu, Manorama, Delhi Ganesh, and Nassar play supporting roles. The film was a remake of Balachander's own Telugu film Rudraveena.
Unnal Mudiyum Thambi focuses on the ideological conflicts between 'Bilahari' Marthandam Pillai, a reputed Carnatic musician, and his younger son Udayamoorthy. Pillai's discrimination towards the people belonging to lower caste is met with criticism from Udhayamoorthy, who believes in society's welfare and walks out for good later. The events that led to change in Pillai's views form the remaining part of the story.
Ilaiyaraaja composed the film's soundtrack and background score. R. Raghunatha Reddy was the film's director of photography, R. Bhaskaran edited the film, and Mohanam was the art director. The film was released on 12 August 1988 to positive critical reception.