Krishnan is a common name in South India. Some well known Krishnans are:
- K. S. Krishnan (1898–1961), Indian physicist who codiscovered Raman scattering with his mentor C. V. Raman
- M. Krishnan (1912–1996), pioneering Indian naturalist, photographer and writer
- M. S. Krishnan (geologist) (1898–1970), Indian geologist and geophysicist.
- M. S. Krishnan, Professor of Business Information Technology at the Ross School of Business, University of Michigan, Ann Arbor
- N. S. Krishnan (1908–1957), well known Tamil film comedian
- Ramanathan Krishnan (b. 1937) is a tennis player from Chennai
- Ramesh Krishnan (b. 1971) is a tennis player from Chennai, son of Ramanathan Krishnan
- Trisha Krishnan, a South Indian film actor
- Ramya Krishnan, a South Indian film actor
Krishnan is also combined with other names into a single name such as Ananthakrishnan, Balakrishnan, Jayakrishnan, Muralikrishnan, Ramakrishnan, Radhakrishnan and Venkatakrishnan.