The hero of the 1997 Lions tour follows Gatland, Shaun Edwards and Rob Howley in signing new deals with the Welsh Rugby Union, while forwards coach Robin McBryde has also been handed a seven-month extension to his current contract.
"Neil is a unique individual, with a unique set of skills," said WRU group chief executive Roger Lewis.
"He's one of the great points-scorers of all time, an amazing coach, an amazing mentor and you couldn't meet a nicer, more honest man.
"There's always been offers for all of our coaches consistently over the past four years and Neil is a person who will be in huge demand. That's why I'm so pleased we've secured his services for the foreseeable future."
Jenkins, who scored a then-world record 1,049 points in Test-match rugby for Wales and the Lions, began working with the WRU Academy set up seven years ago before taking on the role of part-time kicking skills coach with the national side two seasons later.
He was part of Gareth Jenkins' coaching team at the 2007 World Cup and worked with the Lions on their 2009 tour of South Africa.
But while Jenkins' long-term future appears to have been settled, fellow former Lion McBryde has only been offered a short-term deal to remain with Wales amid rumours that England scrum coach Graham Rowntree may be a WRU target.
McBryde, who was a Lion under Graham Henry in 2001, has also worked with the Scarlets but Gatland is keen to dismiss talk that the Wales ex-hooker could be surplus to requirements further down the line.
"I want to give some credit to Robin McBryde and the great job he has done," said Gatland.
"Robin has signed up to the end of the season and we'll make a decision on his future after that.
"As a young coach he has improved enormously in the last two or three seasons and I don't think you throw away that experience that he has developed over the last five or six years.
"I would hate to see that investment of time and effort and energy lost to Welsh rugby. I'm very conscious of making sure he won't be left out in the cold."