Gundappa Ranganath Viswanath (born 12 February 1949) is a former Indian cricketer. Vishwanath was rated as one of India's finest batsmen throughout the 1970s. Viswanath played Test cricket for India from 1969 to 1983, making 91 appearances and scoring more than 6,000 runs. He also played in One Day Internationals from 1974 to 1982, including the World Cups of 1975 and 1979. He is the only cricketer to score a double century on debut in a first-class match (against Andhra Pradesh in 1967) and a century on debut in a Test match.