Sunil Gangopadhyay or Sunil Ganguly (7 September 1934 – 23 October 2012) was an Indian poet and novelist in the Bengali language based in the city of Kolkata. He is a former Sheriff of Kolkata. 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 Kakababu series 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 nom de plume Nil Lohit, Sanatan Pathak, and Nil Upadhyay. He was one of the most popular, creative and celebrated Bengali Writers of the present era.