Viswanathan is an Indian surname and given name. It is of Hindu origin and derives from višvanatha, meaning "lord of the universe" (from višva, "universe" + natha, "lord," an epithet of the god Shiva), + the Tamil-Malayalam third-person masculine singular suffix -n. Although used as a given name in India, it has also come to be used as a family name in the United States.

It may refer to:

  • Ed Viswanathan (born 1942), Indian writer and engineer
  • Kaavya Viswanathan (born 1987), Indian-American Harvard undergraduate student, noted for plagiarism in her 2006 novel
  • M. S. Viswanathan, Tamil film music composer
  • T. Viswanathan, (1927-2002), South Indian classical Carnatic fluteist
  • Viswanathan Anand (born 1969), World Chess Champion since 2007