Samuel Lester "Slam" Agnew (April 12, 1887 – July 19, 1951) was an American professional baseball catcher.

He played in Major League Baseball from 1913 through 1919 for the St. Louis Browns, Boston Red Sox and Washington Senators.

In 105 games his rookie season, Sam hit .208 with 2 home runs and 24 RBI, stealing 11 bases, in 307 at bats.

During a late season Red Sox game, a fight broke out after Carl Mays hit a Washington player with a pitch.

In a seven-season career, Agnew posted a .204 batting average with two home runs and 98 RBI in 563 games played.