Marcus Albert Foster (March 31, 1923 – November 6, 1973) was a respected African-American educator who gained a national reputation for educational excellence while serving as principal of Simon Gratz High School in Philadelphia, Pennsylvania, as Associate Superintendent of Schools in Philadelphia, and as the first black Superintendent of the Oakland Unified School District in Oakland, California. Foster was murdered in 1973 by members of the Symbionese Liberation Army.

He was born in Athens, Georgia, later attending public schools in Philadelphia. He graduated from Cheyney State College and earned a doctorate from the University of Pennsylvania. He was also a member of Omega Psi Phi Fraternity, Inc.

From 1957 to 1970 he taught, was a school principal and associate superintendent for community relations. He moved to Oakland in 1970.

Foster was murdered in 1973 by members of the Symbionese Liberation Army. The SLA claimed they killed Foster because of his alleged support of a plan to create a student identification card system in Oakland that proponents claimed would help keep non-student drug-dealers off campus. In reality, Foster had opposed the identification cards and had worked to water down the plan. The SLA also objected to police officers in the schools, but again they were mistaken as to Foster's position; Foster had stated that he would not allow police officers in the schools. Foster was shot eight times with bullets that had been dipped in cyanide. His deputy, Robert Blackburn, was also shot, but survived. Joseph Remiro and Russ Little were sentenced to life in prison for their role in the attack. Little was later released on appeal. SLA leader Donald DeFreeze is suspected of being the other person present who shot Blackburn.