Jeffrey Allen Lahti (born October 8, 1956, in Oregon City, Oregon) was a Major League Baseball pitcher. He is an alumnus of Portland State University.
Drafted by the Cincinnati Reds in the 5th round of the 1978 MLB amateur draft, Lahti would make his Major League Baseball debut with the St. Louis Cardinals on June 27, 1982, and appear in his final game on April 24, 1986.
Lahti was a member of the St. Louis Cardinals team that defeated the Milwaukee Brewers in the 1982 World Series.
He led the 1985 Cardinal team that went to the World Series in saves a year after the departure of relief ace Bruce Sutter. He was injured early in the 1986 season and Todd Worrell took over as the closer and won National League Rookie of the Year Award.
Lahti was often called Lahti-Da by his teammates.