The Americans led 52-29 at half-time on their way to winning the title for the 15th time in 19 stagings.
Kevin Durrant, part of the victorious American team at London 2012, scored 30 of his side’s points.
Spain, beaten finalists at the past two Olympic Games, won the bronze medal in Rio as they defeated Australia 89-88 in a thrilling finish.
The US’ winning margin was the biggest in a men’s Olympic basketball final since they beat Croatia 117-85 in Barcelona in 1992.
Team finish USA top of the medal table with 46 golds, 37 silvers and 38 bronzes in an overall total of 121.