M. Krishnan Nair may refer to:
- M. Krishnan Nair (author) (1923–2006), Malayalam literary critic and orator
- M. Krishnan Nair (doctor), retired director of the Regional Cancer Centre in Thiruvananthapuram, Kerala
- M. Krishnan Nair (director) (1917–2001), Indian film director of Malayalam films
- M. Krishnan Nair (politician) (1870–1938), member of Madras Legislative Council