Sunil Gangopadhyay or Sunil Ganguly was an Indian poet, historian, and novelist in the Bengali language based in the city of Kolkata. He is a former Sheriff of Calcutta. Gangopadhyay obtained his master's degree in Bengali from the University of Calcutta.

Sunil Gangopadhyay or Sunil Ganguly (7 September 1934 – 23 October 2012) was an Indian poet, historian, and novelist in the Bengali language based in the city of Kolkata. He is a former Sheriff of Calcutta. 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 whose real name is Raja Roy Chowdhury and his passion is to solve mysteries. He wrote 36 novels in the Kakababu series which became significant in Indian children's literature. He received the Sahitya Akademi award in 1985 for his novel Those Days (Sei Samay). Gangopadhyay used the pen name Nil Lohit, Sanatan Pathak, and Nil Upadhyay. He is regarded as one of the most popular, creative, and celebrated Bengali Writers of the present era.