Oscar Marion Fritz (March 3, 1878 – October 5, 1957) was an American lawyer and jurist from the U.S. state of Wisconsin.

During his childhood, his father served four years (1887–1891) in the Wisconsin State Senate, representing part of the city of Milwaukee as a member of the socialist Peoples' Party.

[1] From 1901 through 1912, Fritz practiced law in Milwaukee in partnership with Theodore Kronshage, Francis E. McGovern, Guy D. Goff, Walter D. Corrigan, and Timothy J.

Ena died in 1945, and, two years later, Judge Fritz married Anna Marie Millmann of Milwaukee, who was then a member of the board of directors of the Marquette University Alumni Association.

He was cremated and interred alongside his first wife at Milwaukee's historic Forest Home Cemetery.