The 1939–40 Ranji Trophy was the sixth season of the Ranji Trophy. Eighteen teams took part in four zones in a knockout format. Northern India who appeared in the previous season dropped out but would return in 1940–41. Maharashtra won their first title defeating United Provinces in the final.

The Ranji Trophy is a premier domestic first-class cricket championship played in India and organized annually by the Board of Control for Cricket in India (BCCI). The teams representing regional and state cricket associations participate. BCCI founded the championship in 1934, Since then it has been organised across various grounds and stadiums in India.