Sunil Gangopadhyay or Sunil Ganguly (Shunil Gônggopaddhae), (7 September 1934 – 23 October 2012) was an Indian Bengali poet and novelist based in the Indian city of Kolkata. Born in Faridpur, in what is now Bangladesh, Gangopadhyay obtained his master's degree in Bengali from the University of Calcutta. In 1953 he and a few of his friends started a Bengali poetry magazine, Krittibas. Later he wrote for many different publications.

Ganguly created the Bengali fictional character Kakababu and wrote a series of novels on this character which became significant in Indian children's literature. He received Sahitya Akademi award in 1985 for his novel Those Days (Sei Samaya). Gangopadhyay used the pen names Nil Lohit, Sanatan Pathak, and Nil Upadhyay.