Jonas D. Jennings (born November 21, 1977 in College Park, Georgia) is an American football player who currently plays offensive tackle for the San Francisco 49ers of the National Football League. He was drafted by the Buffalo Bills in the third round (95th pick overall) of the 2001 NFL Draft. He went to University of Georgia. On October 4, 2007 Jonas Jennings took a leave of absence from the San Francisco 49ers to deal with 'private matters'. He was replaced by Adam Snyder for the week 5 game against the Baltimore Ravens. It was announced the week after that he will rejoin the team as the starter at LT, but during the next game against the New York Giants he split time with his backup Adam Snyder.

Jennings sustained a high ankle sprain in the second quarter of the 49ers' loss to the Giants on October 21st and missed the subsequent two games. On November 5th he was placed on Injured Reserve; coach Mike Nolan stated that Jennings was to undergo surgery to remove "loose bodies" in his ankle, effectively ending his 2007-2008 season.