Terms were not released but the Miami Herald reported the six-year deal worth $96 million with $45 million guaranteed.
Tannehill, 26, the eighth pick in the 2012 draft, has started all 48 games in his three seasons with the Dolphins and his numbers have improved each season.
He has completed 1,029 passes for 11,252 yards, 63 touchdowns and 42 interceptions, and rushed for 760 yards and four touchdowns.
Tannehill’s new contract comes only a few months after speculation that he would lose his spot as the starting quarterback.
In September, coach Joe Philbin refused to confirm that Tannehill would start the next game, but the player ultimately got the nod and did enough the rest of the season to impress the front office.
The Dolphins have not made the playoffs since 2008, and they are 23-25 in three seasons with Tannehill.
???We are thrilled that we were able to sign Ryan to an extension,??? said Dolphins Executive Vice President of Football Operations Mike Tannenbaum.
???He is an ascending talent, a team leader and checks all of the boxes you are looking for at the position.???
Dolphins General Manager Dennis Hickey added: ???Signing Ryan to this deal is important to our franchise.
???He is a proven quarterback in this league that combines a talented skillset with work ethic, passion, toughness, and a team first mentality.
???We are committed and believe in Ryan as our quarterback for the long-term and we are excited to be able to sign him to this extension.???