A team option for 2020 called for Parker to make a $4.4 million salary, but his play prompted the Dolphins to lock him up longer.
Parker has played 13 games with 11 starts, making 55 catches for 882 yards and six touchdowns. His receiving yards are a career best as are his touchdowns.
He originally entered the NFL as the 14th overall choice of the Dolphins in 2015.
Parker was diagnosed with a concussion last week and is questionable for Sunday’s game against the Giants.