Kalpnath Rai (4 January 1941 – 6 August 1999) was an Indian politician. He served as a member of the Rajya Sabha between 1974–80, 1980–86, and 1986–92, as well as being elected on four occasions to the Lok Sabha from the Ghosi constituency in the state of Uttar Pradesh. He was a minister in various national Congress (I) governments. Rai is credited with giving Mau the status of a district during his days as an MP from Ghosi.