Guillermo Jaime Jorrin (born November 21, 1969), better known as Willie Jorrin, is a boxer from Sacramento, California. Jorrin is a Mexican-American. He is considered by many to be one of the top competitors in boxing's Super-Bantamweight and Featherweight divisions area.

Jorrin debuted as a professional boxer on February 12, 1993, with a first round knockout victory over Esau Diegues. This was the first of three consecutive first round knockout victories for Jorrin. On October 1 of that year, Pat Chavez became the first person to last the distance with Jorrin, losing a six round decision to the Sacramento fighter.

After sixteen wins in a row, Jorrin faced Enrique Jupiter on June 7, 1997. Jupiter was a ranked contender and Jorrin beat him by a ten round unanimous decision. Jorrin then became a ranked challenger by the WBC. Jorrin outpointed Juan Luis Torres, also over ten rounds, on December 4, to finish 1997.

Jorrin won all three of his fights in 1998, including a four round knockout over Enrique Valenzuela. He kept his winning ways in 1999, winning three fights, among them, a twelve round decision over Aristead Clayton and a five round knockout over Juan Luis Torres in a rematch. After those wins, he was ranked as the world's number one contender by the WBC.

In September of 2000, Jorrin took on the road, going to England, where he became world champion by beating Michael Brodie on September 9 with a unanimous decision for the WBC's world Super Bantamweight title, the same belt that Wilfredo Gómez and Lupe Pintor, among others, had had before Jorrin.

For his first defense, he beat Oscar Larios by a decision in twelve back home in Sacramento on a ESPN televised fight on January 19, 2001. He then went to Japan, where he dropped Osamu Sato in round three of his second defense, but was only given a draw (tie) by the judges on February 5, 2002.

On November 1, he and Larios had a rematch, and this time, Larios defeated Jorrin to take the WBC's world title.

Jorrin started a quest to try to recover his world title almost immediately, and on April 25, 2003, he beat John Hoffman by a knockout in two rounds at Rosemont, Illinois. In his next fight, on November 6 at Phoenix, however, he suffered a setback, losing by unanimous decision in ten rounds to Christen Favela.

Jorrin's record stands at 29 wins, 2 losses and one draw, with 13 wins by knockout.