Allan Huber "Bud" Selig (; born July 30, 1934) is an American baseball executive who currently serves as the Commissioner Emeritus of Baseball. Previously, he served as the ninth Commissioner of Baseball from 1998 to 2015. He initially served as de facto acting commissioner beginning in 1992 in his capacity as chairman of the Major League Baseball Executive Committee before being named the official commissioner in 1998. Selig oversaw baseball through the 1994 strike, the introduction of the wild card, interleague play, and the de facto merging of the National and American Leagues under the Office of the Commissioner. He was instrumental in organizing the World Baseball Classic in 2006. Selig also introduced revenue sharing. He is credited for the financial turnaround of baseball during his tenure with a 400 percent increase in the revenue of MLB and annual record breaking attendance.

During Selig's term of service, the use of steroids and other performance-enhancing drugs became a public issue. The Mitchell Report, commissioned by Selig, concluded that the MLB commissioners, club officials, the Players Association, and the players all share "to some extent in the responsibility for the steroid era." Following the release of the Mitchell Report, Congressman Cliff Stearns called publicly for Selig to step down as commissioner, citing his "glacial response" to the "growing stain on baseball." Selig has pledged on numerous occasions to rid baseball of performance-enhancing drugs, and has overseen and instituted many rule changes and penalties to that end.

A Milwaukee native, Selig was previously the owner and team president of the Milwaukee Brewers. The franchise, originally known as the Seattle Pilots, was acquired by Selig in bankruptcy court in 1970, and renamed after the minor league team of the same name that he had watched in his youth and had existed until the arrival of the Braves in Milwaukee in 1953. Selig was credited with keeping baseball in Milwaukee. The Brewers went to the 1982 World Series (but were defeated in seven games by the St. Louis Cardinals), and Selig won seven Organization of the Year awards during his tenure. Selig remains a resident of Milwaukee.

On January 17, 2008, Selig's contract was extended through 2012, after which he planned to retire, but he then decided to stay as commissioner until the end of the 2014 season, a move approved by the owners on January 12, 2012, which would take his leadership past his 80th birthday. Selig made $14.5 million in the 12-month period ending October 31, 2005. Selig announced on September 26, 2013, that he would retire in January 2015. On January 22, 2015, MLB announced that Selig would formally step down from the office when his current term expired on January 24, 2015. He was inducted into the Baseball Hall of Fame in 2017.