M. Krishnan Nair (November 2, 1917 – May 10, 2001 in Thiruvananthapuram) was an Indian film director of Malayalam films. He directed over 100 films. He also directed four Tamil films starring M. G. Ramachandran. Eminent filmmakers including Hariharan and Bharathiraja apprenticed under him as assistant directors.
He was married to K. Sulochana Dvi, and had three sons. His son K. Jayakumar is a poet, lyricist and a former bureaucrat who currently serves as the Vice Chancellor of Malayalam University.