An outfielder is a person playing in one of the three defensive positions in baseball or softball, farthest from the batter. These defenders are the left fielder, the center fielder, and the right fielder. As an outfielder, their duty is to catch fly balls and ground balls then to return them to the infield for the out or before the runner advances, if there are any runners on the bases. As an outfielder, they normally play behind the six players located in the field. By convention, each of the nine defensive positions in baseball is numbered. The outfield positions are 7 (left field), 8 (center field) and 9 (right field). These numbers are shorthand designations useful in baseball scorekeeping and are not necessarily the same as the squad numbers worn on player uniforms.

Outfielders named to the MLB All-Century Team are Hank Aaron, Ty Cobb, Joe DiMaggio, Mickey Mantle, Willie Mays, Stan Musial, Pete Rose, Babe Ruth, Ted Williams, Carl Yastrzemski, and Ken Griffey Jr.