Gnanakoothan (7 October 1938) was the pseudonym of the Tamil Poet R. Ranganathan, author of poetry compilations, Anru veru kizhamai, Suriyanukku Pinpakkam, Kadarkaraiyil Sila Marankal, Meendum Avarkal, Collected Poems and Pencil Padangal. He was one of the modern Tamil poet in Tamil literature, and a regular contributor to topical columns in Tamil periodicals such as Kalki, Kalachuvadu and Uyirmei. He was involved with little magazines like Kacatathapara, Maiyam, Vriksham.