The former British and Irish Lions and Wales fly-half and world record points scorer has been an integral part of Warren Gatland's coaching staff, alongside assistant coaches Shaun Edwards, Rob Howley and Robin McBryde, since Gatland's appointment and also joined his colleagues on the coaching staff of the Lions tour of South Africa in 2009.
WRU chief executive Roger Lewis, says Jenkins has a specific set of coaching attributes which make him invaluable to Welsh rugby and he plans to make full use of his skills at all levels of the game.
"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 long term."
Jenkins will continue as National Squad skills coach and, like Edwards and Howley who have both recently re-committed themselves to the national cause as the squad builds for the 2015 Rugby World Cup, he will have daily contact with the WRU National Academy sides when he is not in camp with Wales.
"I couldn't think of anywhere else I'd rather be at the moment than with Wales, there are exciting times ahead of us," said Jenkins.
"We have a great group of young players with the national squad and more coming through the system every year.
"The production line is alive and well in Welsh rugby and we are all relishing the opportunity at national level to work with these young players in the seasons ahead."
WRU head of rugby and performance Joe Lydon said:
"Neil continued commitment to Wales, linked with a desire, matched only by ability, to work to develop the younger talented players is another huge lift for Welsh Rugby.
"Whilst we recognise it would be impossible to replace Neil our collective goal is to identify and develop the next Neil Jenkins, to find another Welsh Rugby great."
Wales head coach Warren Gatland added: "Neil is a rich resource in terms of worldly experience rugby and the technical skills he has at his disposal and is able to bring into his coaching.
"He is known around the world for what he was able to do on a rugby pitch, but he has developed into an astute coach and is an integral part of the current Wales set up.
"What he has offered, and will continue to offer, Welsh rugby is invaluable, he is a huge asset and it is great news for the youngsters coming through that they will be able to reap the benefits of the expertise and knowledge that he possesses about the game in the years ahead."
Wales face Australia at the Millennium Stadium on Saturday, 3 December in a replay of their World Cup bronze medal play-off, with tickets still available from www.wru.co.uk