Jonathan Tiomkin (known as "Jon"; born July 12, 1979, in Brooklyn, New York) is an American Olympic foil fencer.

Fencing for St. John's University, Tiomkin won the bronze medal in foil at the 1999 NCAA Championships,[1] and was a 1st-team All-American.

[5] Tiomkin won the bronze medal in the 2005 Shanghai World Cup.

[7] At the 2004 Summer Olympics, Tiomkin advanced to the round of 32, where he was defeated 3–15 by the number 1 seed, Andrea Cassarà of Italy.

[5][9] Tiomkin, who is Jewish, fenced in the 2001 Maccabiah Games, winning team silver medals in épée and foil.