Squire has signed for both the Highlanders and New Zealand Rugby.
It is another big boost for the Highlanders who now have some of its biggest names signed for at least two more years.
Squire joins the likes of Aaron Smith, Elliot Dixon and Ben Smith on long-term deals which will keep them at the Highlanders through the 2019 season.
Utility back Matt Faddes also announced earlier this month he had signed on until 2019.
Squire, who made his test debut last year, and has played eight tests, arrived at the Highlanders franchise last year as a replacement for the departed Nasi Manu.
He played for the Chiefs for two years prior although he was dogged by concussion issues.
The man from Tasman quickly became a fan favourite with his abrasive style of play and rugged defence, but he is not all smash and bash and has some subtle skills to his game.
He shared the No 8 role with Luke Whitelock last season with Whitelock starting nine times and Squire coming off the back of the scrum in eight games.
Squire (26) started in the opening two games for the Highlanders at No8 this year before succumbing to a knee injury in the second game against the Crusaders.
He was out for more than a month before coming off the bench in the side's narrow win over the Blues on April 8 and is expected to feature against the Sunwolves in Invercargill on Saturday.
The signing of all the players for next year and beyond is a bonus for the side yet to announce its head coach next year.
The Highlanders have constantly said they are in no hurry to appoint a coach and the waiting does not seem to be impacting on the ability to sign players.
Assistant coaches Mark Hammett and Scott McLeod appear to have the inside running to be the new coach but the standard line of ''concentrating on the next game'' is trotted out.
The Highlanders will be now switching their attention on getting outside backs Malakai Fekitoa and Waisake Naholo to sign on the dotted line. The two backs are off contract with the Highlanders at the end of the season.