Thiagaraja Sadasivam (4 September 1902 – 21 November 1997), better known as Kalki Sadasivam, was an Indian freedom fighter, singer, journalist and film producer who was one of the founders, along with Kalki Krishnamurthy of the Tamil magazine Kalki. He is well known as the husband of famous classical carnatic singer M.S. Subbulakshmi.