List of world welterweight boxing champions

Beginning with Mysterious Billy Smith to Harry Lewis, the welterweight world champions listed below are more widely recognized in the United States and are not as widely sanctioned as the boxers that follow. Beginning with boxer Pat Bradley, is a chronological widely recognized List of World Welterweight Boxing Champions, as recognized by four of the better-known sanctioning organizations:

• The World Boxing Association (WBA), founded in 1921 as the National Boxing Association (NBA)
• The World Boxing Council (WBC), founded in 1963
• The International Boxing Federation (IBF), founded in 1983
• The World Boxing Organization (WBO), founded in 1988