In Major League Baseball (MLB), the 3,000 strikeout club is the group of 19 pitchers who have struck out 3,000 or more batters in their careers. Walter Johnson became the first member in 1923, and was the only one until Bob Gibson joined in 1974. The most recent addition is Max Scherzer, who joined on September 12, 2021. The group includes three left-handed pitchers: CC Sabathia, Steve Carlton, and Randy Johnson. Randy Johnson reached the mark with the fewest games pitched and innings pitched. The Minnesota Twins were the first of four franchises to see multiple pitchers record their 3,000th strikeout: Walter Johnson in 1923 and Bert Blyleven in 1986. The other teams with multiple members are the Chicago Cubs, the New York Yankees, and the Houston Astros. César Gerónimo is the only player struck out by two pitchers for their 3,000th strikeout: Gibson in 1974 and Ryan in 1980. Ten 3,000-strikeout pitchers are also members of the 300-win club. Seven members were named to the All-Century Team, a list of MLB's best 100 players; fans later elected four of them as starters. Thirteen members of the club also won a Cy Young Award in their careers.

Walter Perry Johnson, nicknamed "Barney" and "the Big Train", was an American professional baseball player and manager. He played his entire 21-year baseball career in Major League Baseball as a right-handed pitcher for the Washington Senators from 1907 to 1927. He later served as manager of the Senators from 1929 through 1932 and of the Cleveland Indians from 1933 through 1935.