Keith Fitzgerald Thurman Jr. (born November 23, 1988) is an American professional boxer.

He is a former unified welterweight world champion, having held the WBA title from 2015 to 2019 (promoted to Super champion in 2017), and the WBC title from 2017 to 2018

Nicknamed "One Time" for his formidable knockout power, Thurman is considered one of the hardest punchers in the welterweight division.

As of August 2020, he is ranked as the world's fourth best active welterweight by The Ring magazine, fifth by BoxRec, and sixth by the Transnational Boxing Rankings Board.

Thurman's first amateur fight was in 1997.

He was trained by the late Benjamin Getty who worked with Sugar Ray Leonard.

Getty took Thurman under his belt as a child and helped shape him into the fighter he is today. Thurman is now coached by Dan Birmingham.

Thurman finished his amateur career with 101 victories (76 KO's), he won  6 National Championships including the 2006 PAL National Championships.

In 2007 he lost twice to world champion Demetrius Andrade at the Olympic Trials and won the silver medal.