In baseball, a left fielder, abbreviated LF, is an outfielder who plays defense in left field. Left field is the area of the outfield to the left of a person standing at home plate and facing towards the pitcher's mound. In the numbering system used to record defensive plays, the left fielder is assigned the number seven.

Of all outfielders, the left fielder often will have the weakest arm, as he generally does not need to throw the ball as far to prevent the advance of any baserunners. The left fielder still requires good fielding and catching skills, and tends to receive more balls than the right fielder because right-handed hitters tend to "pull" the ball into left field. The left fielder also backs up third base on pick-off attempts from the catcher or pitcher and bunts, when possible. Moreover, when a runner is stealing third base, the left fielder must back up the throw from the catcher. Left fielders must also back up third base when a ball is thrown from right field, and back up center field when a pop fly is hit into the pocket.

The following are baseball players inducted to the National Baseball Hall of Fame as left fielders: