The agency won the work after a pitch against undisclosed agencies, which is understood to have been handled by the London Organising Committee of the Olympic Games.
Glue London, which works on UK digital marketing for Adidas, one of the event's top sponsors alongside Coca-Cola and McDonald's, is unaffected by the appointment and did not pitch for the task.
LOCOG finalised a digital roster in February that includes LBi, Crayon and Code Computerlove. They will work with Chime Communications, which is handling the marketing communications account.
Agency Republic declined to comment. Adidas referred calls to LOCOG.