Vadayil Sankaran Vijayan is an Indian environmentalist, wildlife biologist, ornithologist, an admirer of naturopathy and the founding Director of the Salim Ali Centre for Ornithology and Natural History. He is currently the chairman of the Salim Ali Foundation. He obtained Ph.D in Field Ornithology in 1976 from the University of Bombay for his work on the Ecological isolation in bulbuls under the guidance of Salim Ali. He is married to Lalitha Vijayan, a noted ornithologist, a Ph D. student of Salim Ali and former scientist of Salim Ali Centre for Ornithology and Natural History. The couple has a son V.V. Robin, an evolutionary biologist.
His report on the Impact of hydroelectric dam on wildlife in Silent Valley was the first scientific basis for the start of the Save Silent Valley movement. The long term studies conducted under his leadership on the ecology of Keoladeo National Park was instrumental in developing management plans for the park.
As the founder Director of the Salim Ali Centre for Ornithology, he led several studies for the conservation of threatened birds of India. He was instrumental in developing the Pupil's Biodiversity Register for each Grama Panchayath in the state of Kerala. He also developed an organic farming policy for Kerala state during his tenure as the Chairman of the Kerala State Biodiversity Board.
He is the recipient of the Padmanabhan Memorial award.