Ex-dual-code international Harris added: "I am really excited by the opportunity to help Wales Rugby League develop over the coming years and to bring through the young players who are showing such talent.
"Clive has been a big influence on my career over the last 15-20 years and he will bring a lot of experience and act as a father-figure to the players."
In addition to having Griffiths at his side, Harris' coaching development is expected to progress alongside Brian Noble, the Wigan coach tipped to be the Crusaders' new boss in the wake of John Dixon's departure.
Wales play four games this autumn, starting with a friendly against England at Bridgend's Brewery Field on Saturday, 17 October.
Wales then travel to Serbia on Sunday, 25 October for their first European Cup game before taking on Ireland in Pontypridd on Sunday, 1 November.
Harris named Wales coach
The tournament climaxes with three games in a day in Bridgend on Sunday, 8 November.
Wales Rugby League executive chairman Mark Rowley said: "We're delighted that Iestyn Harris has accepted the role of head coach.
"He has the enthusiasm and passion for the development of rugby league in Wales and it is these elements that will help him be a success.
"We are also delighted that someone of the calibre of Clive Griffiths is assisting him.
"While Clive hasn't been involved with the full Wales set-up since 2000, he's not been out of rugby league and successfully led the Wales Students side to the World Cup semi-finals last year.
"We are sorry to see John Dixon leave and we wish him well as he returns to a new coaching position in Australia.
"Over the last four years, John has laid the foundations for the success of rugby league in Wales and for that we owe him a great deal of thanks."
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