Henry Stapp is an American physicist, known for his work in quantum mechanics, particularly the development of axiomatic S-matrix theory, the proofs of strong nonlocality properties, and the place of free will in the “orthodox” quantum mechanics of John von Neumann.

Stapp earned a BS in Physics from the University of Michigan, and an MA in Physics from the University of California, Berkeley. He later received his PhD in Particle Physics at the University of California under the supervision of Nobel Laureates Emilio Segrè and Owen Chamberlain, during which time he worked as a research physicist at the Lawrence Radiation Laboratory. He is retired from Lawrence Berkeley National Laboratory, but remains a member of its scientific staff.

Stapp has served as a visiting scientist at many institutions abroad, including the Eidgenossiche Technische Hochschule in Zurich, the International Center for Theoretical Physics in Trieste, the Middle East Technical Institute in Ankara, the Centre for European Nuclear Research in Geneva, and the Centre d’Etudes Nucleaire in Saclay.