William Nathaniel "Buck" Showalter III (born May 23, 1956) is an American professional baseball manager for the New York Mets of Major League Baseball (MLB). Previously, he served as manager of the New York Yankees (1992–1995), Arizona Diamondbacks (1998–2000), Texas Rangers (2003–2006), and Baltimore Orioles (2010–2018). He also is a former professional Minor League Baseball player and television analyst for ESPN and for the YES Network for Yankees telecasts.

A three-time American League (AL) Manager of the Year, Showalter has earned a reputation for building baseball teams into postseason contenders in short periods of time.[1] He helped the Yankees rise from the bottom half of the AL East to first place before a players' strike prematurely ended the 1994 campaign.[2] Under his watch, the Diamondbacks made their first-ever playoff appearance in only the second year of the team's existence.[3] He left both franchises just prior to seasons when they won the World Series.[1]