M. R. Krishnamurthy (1940–2012) who was popularly referred to as MRK, was an Indian actor and stage artist who appeared in Tamil films.

[1] MRK's significant films are; Veetula Raman Veliyila Krishnan, Pondatti Thevai and Ulle Veliye and the Rajini-starrers Dharmathin Thalaivan and Arunachalam.

He has also worked with Kamal Haasan in the film Maharasan and with Vikram in Dhill.

MRK worked as an assistant director under the late and legendary director C. V. Sridhar in a solitary film Oru Odai Nadhiyagiradhu which had the late Raghuvaran playing the lead role.

He had also played significant roles in drama troupes, ran by the likes of V. Gopalakrishnan and Senthamarai, both of whom were popular actors in films as well as on stage.