Karthik Raja (born 29 June 1973) is an Indian composer and playback singer based in Chennai.

His brother Yuvan Shankar Raja and sister Bhavatharini, also Tamil film music directors and playback singers, have worked with him on notable projects.

Born to a family of musicians, Raja had exposure to various kinds of music from a very early age.

At the age of 13, Karthik Raja played the keyboard for the song Kannukkum from the Tamil movie Ninaikka Therinda Maname (1987).

Raja debuted as a fully-fledged composer in 1996 through the Tamil movie Alexander, soon followed by Manikkam.