Kalidas Nag (Bengali: Kalidas Nag; 16 January 1892 – 9 November 1966) was an Indian historian, writer and parliamentarian. He was nominated to the Rajya Sabha in 1952 and served till 1954.

Kalidas was born to Babu Matilal Nag. He married Shrimati Santa Devi, daughter of Ramananda Chatterjee. Together they had three daughters.^[1]

After graduating in history from the Scottish Church College, he earned a postgraduate degree from the University of Calcutta, and a doctorate from the University of Paris.^[2][1] A prolific author, he taught history at the Scottish Church College and at University of Calcutta, and was nominated as an Officer d’ Academic by the Government of France.^[1][3] In the 1920s he was an avid supporter of the French contribution to Tagore's university project at Santiniketan (north of Calcutta). He later edited several books on Indian culture.

• Kalidas Nag (1957). Discovery of Asia, The Institute of Asian African Relations, Calcutta.