Frederick K. "Fritz" Heisler (May 18, 1915 – March 11, 1982) was a professional American football coach who was an assistant and scout for the Cleveland Browns for 30 years between 1946 and 1976.

[1] He made the team under head coach Paul Brown, however, and was a regular starting in 1933, the first of a series of strong seasons.

[4] Brown brought Heisler onto his staff as a guard coach, tutoring linemen on both offense and defense.

[5] Heisler coached players including Bill Willis and Weldon Humble as the Browns won all four of the AAFC's championships between 1946 and 1949.

[8] He stayed on after Brown was fired in 1963, and remained Cleveland's top offensive line coach until retiring in 1971.

[1] He suffered a stroke in 1977 that limited him physically, and he died five years later at the Cleveland Clinic during brain surgery.