Marcelo Gleiser is a Brazilian physicist and astronomer, currently a professor of philosophy, physics, and astronomy at Dartmouth College. Gleiser received his bachelor's degree from the Pontifícia Universidade Católica do Rio de Janeiro, his M.Sc. from the Universidade Federal do Rio de Janeiro, and his Ph.D. from King's College, London. He has taught at Dartmouth since 1991.

Gleiser's research interests currently focus on the physics of the early universe and questions related to the origin of life. He is the author of The Dancing Universe (1997), The Prophet and the Astronomer (2002), and A Tear in the Edge of Creation (2010). He is the co-founder of the science and culture blog 13.7, hosted by National Public Radio.