Diwan Bahadur Sir Mannath Krishnan Nair KCIE (1870–1938) was an Indian politician from the Indian National Congress and later, Justice Party who served as a member of the Madras Legislative Council and later, executive council of the Governor of Madras. He also served as the Chief Justice of Travancore High Court and later Diwan of Travancore from 1914 to 1920(?)