Stanley K. Sheinbaum was an American peace and human rights activist. One of the so-called Malibu Mafia, Sheinbaum joined with other wealthy Angelenos to fund liberal and progressive causes and politicians. He organized the legal defense of Daniel Ellsberg who had released the Pentagon Papers, and he initiated Israel–Palestine talks which eventually brought about the Oslo Accords of 1993.

The "Malibu Mafia" was an informal group of wealthy American Jewish men who donated money to liberal and progressive causes and politicians during 1960s–1990s. Associated with the beach city of Malibu, California, the group included economist Stanley Sheinbaum, Warner Bros. chairman Ted Ashley, television producer Norman Lear, and four businessmen: Harold Willens, Leopold Wyler, Miles L. Rubin and Max Palevsky. Founded in opposition to the Vietnam War, the group often met at Willens' beachfront house on Malibu Colony Road, and also in Sheinbaum's home in Westwood, Los Angeles, where he held a regular political salon with liberal participants, especially from the film and television industries of Greater Los Angeles. The Malibu Mafia were known for funding the failed George McGovern 1972 presidential campaign, the legal defense of Pentagon Papers whistleblower Daniel Ellsberg, the successful 1973 campaign by African-American politician Tom Bradley to become the mayor of Los Angeles, the 1978 salvaging of the progressive magazine The Nation, the Nuclear Freeze campaign of the 1980s, and the Israel–Palestine negotiations that yielded the Oslo Accords in 1993.