Jay Scot Baller (born October 6, 1960) is an American former pitcher in Major League Baseball (MLB) who played for the Philadelphia Phillies, Chicago Cubs, and Kansas City Royals.

He made his Major League debut with the Phillies as a reliever on September 19, 1982, throwing a scoreless, hitless inning against the Pittsburgh Pirates.

He was one of five Phillies along with Manny Trillo, George Vukovich, Julio Franco and Jerry Willard who were traded to the Cleveland Indians for Von Hayes at the Winter Meetings on December 9, 1982.

Baller split the 1986 season between the Triple-A Iowa Cubs and Chicago, sporting a 5.37 ERA, a 2–4 record and five saves in 36 games in the majors, the most extensive big-league action of his career.

After the season Baller signed with the Montreal Expos organization, and became a full-time closer for their Triple-A team, the Indianapolis Indians, posting a career-high 34 saves and a 2.02 ERA.

In between, Baller played winter ball with the Águilas del Zulia, Leones del Caracas and Tiburones de La Guaira clubs of the Venezuelan League in five seasons spanning 1982–1993, posting a collective record of 13–11 and a 2.39 ERA in 136 appearances, garnering three Closer of the Year awards while setting an all-time league record with 56 saves that still remain intact.