Jonathan Robert Papelbon (born November 23, 1980 in Baton Rouge, Louisiana) is the closer for the Boston Red Sox. He bats and throws right-handed.

Papelbon was drafted by the Boston Red Sox in 2003 out of Mississippi State. Papelbon throws a fastball clocked as high as 99 mph, typically hitting the mid-90s, with great command. He complements his fastball with a devastating splitter, and may throw the occasional slider, changeup, or curveball with far less frequency.

He was the Red Sox closer during most of 2006. In early September, Papelbon injured his shoulder; when the Red Sox were eliminated from playoff contention, he was "shut down" for the rest of the season to rest. Papelbon was being groomed to be part of the Red Sox starting rotation because of his shoulder problems, but was later moved back to the bullpen before the start of the season and remained the team's closer. On August 21, 2007, Papelbon had his 30th save of the season making him the first Boston pitcher to ever have two 30-save seasons.

Jonathan is the older brother of twins Joshua Papelbon, pitcher for the Greenville Drive, Class A affiliate of the Boston Red Sox, and Jeremy Papelbon, pitcher for the Boise Hawks, Class A affiliate of the Chicago Cubs.