G. Nammazhvar (Tamil : கோ. நம்மாழ்வார், 6 April 1938 – 30 December 2013) was an Indian green crusader, agricultural scientist, environmental activist and organic farming expert best known for his work on spreading ecological farming and organic farming. He led the protest against the methane gas project started by Great Eastern Energy Corporation proposed in the Cauvery delta region of Tamilnadu. Nammazhvar was the author of several Tamil and English books on natural farming, natural pesticides & natural fertilizers and was featured in magazines & television programs.