The SLAC Site Office (SSO) is an organization within the U.S. Department of Energy's Office of Science with responsibility to oversee and manage the Management and Operating (M&O) contract for the SLAC National Accelerator Laboratory (SLAC) in Menlo Park, California.

SLAC is one of ten Office of Science Laboratories and is a multi-program laboratory with a primary mission on delivering breakthrough science and technology in the area of High Energy Physics and Basic Energy Sciences. The SSO is responsible for program implementation, acquisition management, and laboratory stewardship at SLAC. Through its oversight role, the SSO is affecting the safe and efficient operation of SLAC while enabling the pursuit of visionary research and development in support of DOE's missions.