**Grigory Isaakovich Barenblatt** (Russian: Григо́рий Исаа́кович Баренблат; born July 10, 1927) is a Russian mathematician.

He graduated in 1950 from Moscow State University, Department of Mechanics and Mathematics. He received his Ph.D. in 1953 from Moscow State University under the supervision of A. N. Kolmogorov.

He also received a D.Sc. from Moscow State University in 1957. He is a Professor in Residence at the Department of Mathematics of the University of California, Berkeley and Mathematician at Department of Mathematics, Lawrence Berkeley National Laboratory. He was G. I. Taylor Professor of Fluid Mechanics at the University of Cambridge from 1992 to 1994 and he has been Emeritus G. I. Taylor Professor of Fluid Mechanics since then. His areas of research are:

- Fracture mechanics
- The theory of fluid and gas flows in porous media
- The mechanics of a non-classical deformable solids
- Turbulence
- Self-similarities, nonlinear waves and intermediate asymptotics.