Sujatha (Tamil: சுஜாதா) was the pseudonym of the Tamil writer S. Rangarajan, author of over 100 novels, 250 short stories, ten books on science, ten stage plays, and a slim volume of poems. He was one of the most popular writers in Tamil literature, and a regular contributor to topical columns in Tamil periodicals such as Ananda Vikatan, Kumudam and Kalki. He had a wide readership, and served for a brief period as the editor of Kumudam, and has also written screenplays and dialogues for several Tamil movies.

Sujatha received an award from Government of India's National Council for Science and Technology in 1993 for making science accessible to the public through his books, magazine contributions and other media.