Sidney Altman is a Canadian molecular biologist, who is currently the Sterling Professor of Molecular, Cellular, and Developmental Biology and Chemistry at Yale University. In 1989 he shared the Nobel Prize in Chemistry with Thomas R. Cech for their work on the catalytic properties of RNA.

He received his bachelor's degree in physics from MIT in 1960, spent 18 months as a graduate student in physics at Columbia University, waiting unhappily for an opportunity to work in a laboratory and wondering if he should continue in physics.
After working on the effects of acridines on the replication of bacteriophage T4 DNA, he joined Mathew Meselson's laboratory at Harvard University to study a DNA endonuclease involved in the replication and recombination of T4 DNA where he earned a Ph.D. in biophysics from University of Colorado Medical Center in 1967.
His career at Yale followed a standard academic pattern with promotion through the ranks until he became Professor in 1980. He was Chairman of his department from 1983–1985 and in 1985 became the Dean of Yale College for four years. On July 1, 1989 he returned to the post of Professor on a full-time basis.