Lisa Randall (born June 18, 1962) is an American theoretical physicist working in particle physics and cosmology. She is the Frank B. Baird, Jr. Professor of Science on the physics faculty of Harvard University. Her research includes elementary particles, fundamental forces and extra dimensions of space. She studies the Standard Model, supersymmetry, possible solutions to the hierarchy problem concerning the relative weakness of gravity, cosmology of extra dimensions, baryogenesis, cosmological inflation, and dark matter. She contributed to the Randall–Sundrum model, first published in 1999 with Raman Sundrum.