Oswaldo José Guillén Barrios (Spanish pronunciation: [ɡiˈʎen]; born January 20, 1964) is a Venezuelan former professional baseball player and current manager of the Tigres de Aragua of the Venezuelan League. He played in Major League Baseball as a shortstop from 1985 to 2000, most prominently as a member of the Chicago White Sox, where he won the American League Rookie of the Year Award as well as a Gold Glove Award. A three-time All-Star player, Guillén was considered one of the best defensive shortstops of his era. He later managed the Chicago White Sox from 2004 to 2011, winning the World Series in 2005 and then moving to the Miami Marlins in 2012.
As a player, Guillén was known for his passion, speed, hustle, intensity, defensive abilities and his ebullient love for the game. In 2005, Guillen became the first Latino manager in major league history to win a World Series when he captained the Chicago White Sox to their first championship in 88 years.
Guillén was a light-hitting, quick-handed shortstop, emerging from a line of Venezuelan shortstops that included Chico Carrasquel, Luis Aparicio (both White Sox players), Dave Concepción, and Omar Vizquel (who Guillen later managed with the White Sox). He was originally signed as a free agent by the San Diego Padres in 1980. In December 1984, he was traded to the Chicago White Sox as part of an eight-player trade, with Tim Lollar, Bill Long and Luis Salazar in exchange for LaMarr Hoyt.
In 1985, Guillén was both the American League Rookie of the Year and The Sporting News Rookie of the Year, while also becoming just the third rookie shortstop in major league history to win a fielding title. He became known for his daring, aggressive style of play, as was demonstrated on August 2, 1985, in a game against the New York Yankees. With the game tied 5–5 in the 11th inning, Guillén hit a two-out single and, then proceeded to steal second base. When the next batter hit an infield single, Guillén never hesitated as he rounded third base, catching the Yankees defense off guard and scored the game-winning run.
In 1989, Guillén was the victim of a hidden ball trick twice. First on June 23 when Greg Brock tagged him out when Guillén, the runner at first base, took his lead, and then had to dive back to the base on a pick off throw from the pitcher. Brock held the ball instead of throwing it back to the pitcher, and when Guillén took his hand off the base to stand up, Brock tagged him out. On August 5, Dave Bergman made the same play, holding onto the ball following a pick off throw. Guillén again dove to the base to beat the throw, and when he took his hand off the base to stand up, Bergman tagged him on top of the batting helmet without looking at him.
On April 21, 1992, Guillén suffered a severe knee injury in a collision with outfielder Tim Raines. The injury caused him to miss almost the entire season, and subsequently diminished his defensive range as well as his stolen base output for the remainder of his career. Guillén recovered in 1993 with his most productive season offensively, posting a .280 batting average, and he hit a career-high four home runs and had 50 runs batted in (RBI) in 134 games. The White Sox went on to win the American League Western Division title. He hit .273 and scored four runs in the 1993 American League Championship Series as the White Sox were defeated by the Toronto Blue Jays in six games.
In October 1997, after 13 seasons with the White Sox, Guillén elected free agency and signed a contract to play for the Baltimore Orioles. In May 1998, the Orioles released him, and he signed with the Atlanta Braves. He helped Atlanta win the 1999 National League Championship Series against the New York Mets with a 10th inning, pinch hit single in Game 6 that tied the score at nine runs apiece, as the Braves went on to win the game and the series. The Braves would eventually lose to the New York Yankees in Guillén's only World Series appearance as a player. After playing one year with the Tampa Bay Devil Rays in 2000, he retired as a player at the end of the season at the age of 36.
In a 16-year major league career, Guillén played in 1,993 games, accumulating 1,764 hits in 6,686 at bats for a .264 batting average along with 28 home runs, 619 RBI, and a .287 on-base percentage. Guillén was an All-Star in 1988, 1990, and 1991 and won a Gold Glove Award in 1990. He led American League shortstops twice in range factor, once in assists, and once in fielding percentage. Guillén's .974 career fielding percentage ranks 63rd all time among major league shortstops as of 2024, ahead of, among others, of both Luis Aparicio and Dave Concepción. While he was considered one of the best fielding shortstops in the American League, Guillén was often overlooked in post-season fielding awards because his playing career coincided with those of Tony Fernandez, Cal Ripken Jr., and Omar Vizquel. This trio would win every American League Gold Glove for a shortstop from 1986 until 2001, aside from Guillén's win in 1990. Guillén ranks among the White Sox all-time leaders in games played (sixth), hits (seventh), at-bats (sixth), plate appearances (seventh), total bases (10th) and triples (10th). As a hitter, he was known as a free swinger, posting one of the highest at bats per walk ratios in major league history and also one of the lowest on base percentages for many of the years he played.
Guillén played his entire Venezuelan Winter League career with Tiburones de La Guaira.
Following his playing career, Guillén coached for the Montreal Expos in 2001 and 2002 and the World champion Florida Marlins (now known as the Miami Marlins) in 2003. That offseason, he replaced Jerry Manuel as the White Sox manager. He received a standing ovation from the crowd of 37,706 fans when introduced before his first game as a manager at U.S. Cellular Field on April 13, 2004. On May 30, 2005, the White Sox extended Guillén's contract, making the move while the team had the best record in the majors (33–17).
In 2005, he led the White Sox to their first American League pennant since 1959, and their first World Series win since 1917 with a four-game sweep of the Houston Astros. Guillén claimed that he might retire after the 2005 season should the White Sox win the World Series, but at the parade celebrating the World Champions he received cheers from the fans when he announced he would indeed return to manage the next season. The White Sox picked up the 2006 option on his contract, added two more years and included an option for the 2009 season. In November, Guillén was voted the 2005 American League Manager of the Year Award by the Baseball Writers' Association of America. On September 11, 2007, Guillén signed another contract extension with the White Sox through the 2012 season.
On September 4, 2009, Guillén won his 500th game as manager of the Chicago White Sox as the White Sox defeated the Boston Red Sox by a score of 12–2. Guillen has publicly stated that he feels the 2003 steroids list should be released to the public.
Personal difficulties with White Sox General Manager Kenny Williams led to speculation dating back to October 2010 that the White Sox would allow Guillén out of his contract to manage the Marlins. On September 26, 2011, an inability to get a contract extension worked out with the White Sox eventually led to his being released from his position, with the White Sox retaining the right to receive compensation should Guillén manage in the 2012 season. He finished with a record of 678 wins and 617 losses. His #13 jersey was retired by the team on August 8, 2026 in a pregame ceremony attended by many players Guillén played with and coached.
On September 28, 2011, the Miami Marlins introduced Guillén as their new manager. Robin Ventura replaced Guillén as manager of the White Sox. The Marlins sent Jhan Mariñez and Osvaldo Martínez to the Chicago White Sox as compensation for the hiring of Guillén by the Marlins, as Guillen had one year remaining on his contract with the White Sox.