Richard Losick (born 1943) is an American molecular biologist whose research interests include RNA polymerase, sigma factors, regulation of gene transcription, and bacterial development, being especially noted for his investigations of endospore formation in Gram positive organisms such as Bacillus subtilis. Richard Losick is the Maria Moors Cabot Professor of Biology at Harvard University, and a director of the Foundation for Individual Rights in Education. Losick received his bachelor's degree from Princeton University. Along with Daniel Kahne and Robert Lue, he teaches Life Sciences 1a, the introductory Biology/Chemistry course at Harvard College, which is the College's third largest lecture course.
He was the 2007 recipient of the Selman A. Waksman Award in Microbiology from the National Academy of Sciences and the 2009 recipient of the Gairdner Foundation International Award. In 2012 he was awarded Louisa Gross Horwitz Prize from Columbia University.