Sidney Drell (born September 13, 1926) is an American theoretical physicist and arms control expert.
He is a professor emeritus at the Stanford Linear Accelerator Center (SLAC) and a fellow at the Hoover Institution. Drell is a noted contributor in the field of quantum electrodynamics and particle physics. The Drell-Yan process is partially named after him. He was one of the winners of the 2000 Enrico Fermi Award.
He co-authored a classic textbook "Relativistic Quantum Mechanics" with James Daniel Bjorken. Drell is active as a scientific advisor to the U.S. government, and is a founding member of the JASON Defense Advisory Group. He is also on the board of directors of Los Alamos National Security, LLC, the company that operates the Los Alamos National Laboratory. He is an expert in the field of nuclear arms control and cofounder of the Center for International Security and Arms Control, now the Center for Inthernational Security and Cooperation. He is now a Senior Fellow at Stanford's Hoover Institution. He is also an accomplished violinist.
Sidney Drell is the father of Persis Drell, the current director of SLAC.