William Louis Veeck Jr. (/ˈvɛk/ VEK; February 9, 1914 – January 2, 1986), also known as "Sport Shirt Bill" and "Wild Bill" was an American Major League Baseball franchise owner and promoter. Veeck was at various times the owner of the Cleveland Indians, the St. Louis Browns, and the Chicago White Sox.

Veeck was the last owner to purchase a baseball franchise without an independent fortune and was responsible for many innovations and contributions to baseball. As owner and team president of the Indians in 1947, Veeck signed Larry Doby, thus beginning the integration of the American League, and the following year won a World Series title.

Unable to compete in the new era of salary escalation ignited by arbitration and free agency, Veeck sold his ownership interest in the White Sox after the 1980 season. He was inducted into the Baseball Hall of Fame posthumously in 1991.

Bill Veeck was born on February 9, 1914, in Chicago. While Veeck was growing up in Hinsdale, Illinois, his father, William Veeck Sr., became president of the Chicago Cubs. Veeck Sr. was a local sports writer who wrote numerous columns about how he would run the Cubs differently, and the team's owner, William Wrigley Jr., took him up on the implied offer. While growing up, the younger Veeck worked as a popcorn vendor for the Cubs and also as a part-time concession salesman for the crosstown Chicago White Sox. Later, in 1937, he came up with the idea of planting ivy on the walls of Wrigley Field. Veeck attended Phillips Academy in Andover, Massachusetts. In 1933, when his father died, Veeck left Kenyon College and eventually became club treasurer for the Cubs. In 1935, he married his first wife, Eleanor.

In 1940, Veeck left Chicago and, in a syndicate with former Cubs star and manager Charlie Grimm, purchased the then-struggling Triple-A Milwaukee Brewers of the American Association. After winning three pennants in five seasons Veeck sold his Milwaukee franchise in 1945 for a $275,000 profit.

In his autobiography Veeck – As in Wreck, Veeck claimed to have installed a screen to make the right field target a little more difficult for left-handed pull hitters of the opposing team. The screen was on wheels, so any given day it might be in place or not, depending on the batting strength of the opposing team. There was no rule against that activity as such, but Veeck then took it to an extreme, rolling it out when the opponents batted, and pulling it back when the Brewers batted. Veeck reported that the league passed a rule against it the very next day. However, extensive research by two members of the Society for American Baseball Research (SABR) suggests that this story was made up or certainly exaggerated by Veeck. The two researchers could not find any references to a moveable fence or any reference to the gear required for a moveable fence to work.

While a co-owner of the Brewers, Veeck served for nearly three years in the United States Marine Corps during World War II in an artillery unit. During this time a recoiling artillery piece crushed his right leg, requiring amputation first of the foot, and shortly after of the leg above the knee. Over the course of his life he had 36 operations on the leg. He had a series of wooden legs and, as an inveterate smoker, cut holes in them to use as ashtrays. Veeck also used the wooden leg in props such as a recreation of iconic Revolutionary War soldiers during the Bicentennial year of 1976. At other times, engaged in intensive trade talks with competing owners, Veeck would complain they were demanding "an arm and a leg" in negotiations, then unbuckle the leg and throw it on the desktop for dramatic effect.

Veeck had been a fan of the Negro leagues since his early teens. He had also admired Abe Saperstein's Harlem Globetrotters basketball team, which was based in Chicago. Saperstein saved Veeck from financial disaster early on in Milwaukee by giving him the right to promote the Globetrotters in the upper Midwest in the winter of 1941–42.