(Tamil: இளையராஜா, ɪləjəɹɑːdʒɑː) (born June 2, 1943 as Gnanadesikan) is an Indian film composer, singer, and lyricist. He has composed over 4,000 songs and provided film scores for more than 800 Indian films in various languages in a career spanning more than 30 years. He is based in Chennai, the fourth largest city in India and the centre of the Tamil film industry (colloquially known as Kollywood).

Ilaiyaraaja was a prominent composer of film music in South Indian cinema during the late 1970s, 1980s and early 1990s. Greene, P.D. 1997. Film music: Southern area. Pp. 542-546 in B. Nettl, R.M. Stone, J. Porter and T. Rice (eds.). The Garland Encyclopedia of World Music. Volume V: South Asia — The Indian Subcontinent. New York: Garland Pub. (p. 544). His work integrated Tamil folk lyricism and introduced broader Western musical sensibilities into the South Indian musical mainstream. He has thrice won the Indian National Film Award for best film scoring.

In the 2000s, he composed a range of non-film music, including religious and devotional songs, an oratorio, and world music. He is married to Jeeva, and the couple's two sons (Karthik Raja and Yuvan Shankar Raja) and daughter (Bhavatharini) are film composers and singers.