Guy Marcos Barnea (Hebrew: ??? ?????; born 9 September 1987 in Omer) is an Israeli swimmer who represented Israel at the 2008 Summer Olympics, and has won three medals at the European Championships.
As of March 2016, he held the Israeli records in the long course 50m backstroke (24.64), the short course 50m backstroke (23.27), and the long course 100m butterfly (51.36).