Jeffrey Leonard (born September 22 1955 in Philadelphia, Pennsylvania) is a former left fielder in Major League Baseball with a 14-year career from to . He currently resides in San Jose, California. He played for the Los Angeles Dodgers, Houston Astros and San Francisco Giants, all of the National League, and the Milwaukee Brewers and Seattle Mariners, both of the American League. He is currently the manager of the Reno Silver Sox of the Golden Baseball League.

He was elected to the National League All-Star team in and to the American League All-Star team in .

Nicknamed "HacMan" after the popular video game PacMan, Leonard was known for his "one flap down" routine: running around the bases after hitting a home run with one arm hanging motionless at his side.

Jeffrey Leonard's greatest moment as a player most likely occurred during the 1987 National League Championship Series while with the San Francisco Giants. During the seven game-long series against the St. Louis Cardinals, Leonard had five runs, ten hits, four home runs, five runs batted in, a batting average of .417, and a slugging percentage of .917. For his performance, Leonard was awarded the 1987 NLCS Most Valuable Player Award. It was also during this NLCS that Leonard would draw ire for a "Cadillac" home run trot; the Cardinals felt he took a little too much time rounding the bases on his home runs, thereby showing up the pitcher. He also acquired the nickname "Penitentiary Face" during this series because of his sour demeanor. Ironically, Leonard's Giants would go on to lose that particular NLCS against the Cardinals. To date, Jeffrey Leonard is the last person to be named the Most Valuable Player of a League Championship Series while a member of the losing team.

On February 28, , Leonard and six others were suspended for the entire season for admitting during the Pittsburgh drug trials that they were involved in cocaine abuse. The suspensions for all seven were avoided after agreeing to large anti-drug donations and community service.