Dennis Lee Eckersley (born October 3, 1954), nicknamed "Eck", is an American former professional baseball pitcher and color commentator. Between 1975 and 1998, he pitched in Major League Baseball (MLB) for the Cleveland Indians, Boston Red Sox, Chicago Cubs, Oakland Athletics, and St. Louis Cardinals. Eckersley had success as a starter, but gained his greatest fame as a closer, becoming the first of two pitchers in major league history to have both a 20-win season and a 50-save season in a career.

Eckersley was elected to the Baseball Hall of Fame in 2004 in his first year of eligibility. He previously worked with NESN as a part-time color commentator for Red Sox broadcasts, and has also worked for Turner Sports as a game analyst for their Sunday MLB Games and MLB postseason coverage on TBS. He retired from NESN in 2022.