Jay Michael DeMerit (born December 4, 1979) is an American retired soccer player who played as a center back.

He played college soccer for the UIC Flames and was in the Chicago Fire Premier development squad, but after not being drafted for Major League Soccer, he moved to look for a club in England. He played for non-league sides Southall and Northwood before signing for Watford of the Championship in 2004. DeMerit played 211 total games for Watford over six seasons, including one in the 2006–07 Premier League, having scored in their victory in the 2006 Football League Championship play-off Final. After his release from Watford, he was the first player signed by the Vancouver Whitecaps FC for their entrance in MLS, where he played four seasons before retiring through injury.

DeMerit was first capped for the United States in March 2007, earning 25 caps up to 2011. He was part of their squads that won the 2007 CONCACAF Gold Cup and came runners-up at the 2009 FIFA Confederations Cup, also featuring at the 2007 Copa América and the 2010 FIFA World Cup.