Jonathan "Jon" Mannah (13 September 1989 – 18 January 2013) was an Australian professional rugby league footballer who played with the Cronulla Sharks and Parramatta Eels in the National Rugby League. His position was at prop. He was the brother of Tim Mannah, who also plays for the Parramatta Eels. Like his brother Tim, he also attended Christian Community High School and served as Vice Captain in his last year of high school during 2007. Jon and Tim both played for the Parramatta Eels through the junior ranks before Jon joined the Cronulla Sharks just prior to the commencement of the 2009 NRL season from Parramatta. In 2011, he scored his first try in first grade for Cronulla in Round 3 against the Panthers. In November 2011, after three seasons with the Sharks he signed with Parramatta, returning to his junior club and to play with his brother, Tim.
Mannah was first diagnosed in 2009 with Hodgkin's lymphoma. He died of the disease on 18 January 2013 at age 23. His funeral was held at Faith Baptist Church Sydney in Regents Park on 21 January 2013.