James Eugene Howarth (born March 7, 1947) is an American former professional baseball outfielder who appeared in 152 games played in the Major Leagues over all or part of four seasons, from 1971 to 1974, for the San Francisco Giants.

After his fourth season in the organization, in 1971, when he batted a lofty .363 in 110 games for Triple-A Phoenix, he was rewarded with a post-September 1 call-up to San Francisco.

In 1972, he was part of a crowded outfield corps that featured Baseball Hall of Famer Willie Mays, in his last campaign as a Giant, in center field—along with multiple All-Star selection and Gold Glove Award recipient Bobby Bonds, future All-Stars Dave Kingman and Gary Matthews, rookie and future eight-time Gold Glove winner Garry Maddox, and veteran Ken Henderson.

When he began 1974 with no hits in four at bats as a pinch hitter and defensive replacement, San Francisco sent him back to Phoenix for more playing time.

But, later that year, Howarth sustained a knee injury and concussion in a home-plate collision, and decided to leave professional baseball.