Frank Rehak (July 6, 1926, in New York City, New York – June 22, 1987, in Badger, California) was an American jazz trombonist. He began on piano and cello before switching to trombone. He worked with Gil Evans and Miles Davis. He also appeared with Davis on the broadcast "The Sounds of Miles Davis."

He had a failed marriage to nightclub dancer Jerri Gray. He also had a heroin addiction, which combined with other financial problems led to his withdrawal from music and lapsing into relative obscurity. In an effort to deal with these issues he spent time at Synanon, which led to his mention in Art Pepper's autobiography. He died in Badger of throat cancer at the age of 60.