Dr. Gangadhar Adhikari (8 December 1898 – 21 November 1981) was a prominent Marxist theoretician and prolific writer as well as one of the main apologists for Islamist separatism in India. He was the former general secretary of the Communist Party of India (CPI), one of the oldest political parties in India. He was a chemical scientist who earned his Ph.D. degree in Berlin in 1927.