Jamaica clocked 37.27 seconds, beating second-placed Japan by 0.33. The United States came third in 37.62 but was disqualified, Xinhua news agency reported.
Canada finished third with a timing of 37.60 seconds to take the bronze medal.
Bolt has won an Olympic sweep of 100m, 200m and 4x100m for the third straight time.
Surprise World Championship 2015 runner-up China was fourth.