Coach McGinty has put pen to paper on an extension to his existing deal to form part of a new-look coaching team at Warriors.
"I'm delighted that Clive is joining the coaching team and Billy has committed himself to Warriors with a new deal," said Director of Rugby Mike Ruddock.
"Clive will be a very positive and driving influence upon the way that we intend to take things forward with the squad. He has a high level of experience and ability having previously coached with Swansea, Newport Gwent Dragons and Wales as well as his huge success in rugby league. He did a great job alongside me with Wales and I'm delighted to once again work together.
"Billy is a very impressive coach and there is no doubt he has contributed greatly to the success of the Warriors over the last few years. Billy will also be key to providing a personal player development programme for each individual at the club that links fully with the great work of the Academy, A team and senior side. He can drive that programme forward as well as providing his expertise at senior level."
Griffiths has enjoyed a glittering coaching career and spent 10 years with the Welsh rugby league team, twice guiding them to the semi-final stage of the World Cup and winning the European Championship for the first time in 57 years. The 53-year-old also enjoyed a spell as Great Britain rugby league coach in 1996.
His first coaching role in union was with London Welsh for three seasons before roles as defence coach with Swansea and Newport Gwent Dragons. He joined the Wales set-up under Graham Henry and had five full seasons with the national side. His latest position was as Director of Rugby at Doncaster.
Griffiths said: "It is another challenge for me and I'm looking forward to linking up with Mike again and working in the Guinness Premiership to help move Warriors forward.
"I've had a fantastic time at Doncaster and leaving was a very difficult decision for me to make, I wish the club and players all the very best for the future. But I believe the time is right for me to make this decision.
"I'm full of confidence that we can be a successful team at Warriors. We know we will need to earn the respect of other teams in the division, but I'm sure we can bring a brand of rugby to the club that supporters will enjoy."
McGinty is a former Wigan rugby league star who represented Great Britain four times, won two Challenge Cups, two Regal Trophies, Premiership and league championships as well as two World Club Championships. He has had spells as assistant coach at Wigan and Huddersfield Giants, head coach for Scotland rugby league team and also in rugby union at Sale.
"I'm very pleased to still be involved at the club and hopefully alongside Mike Ruddock and Clive Griffiths we will keep building on the work we did at the second half of last season," said McGinty. "The team was moving forward and there is still a lot of potential, hopefully we can develop them and become a real force in the Guinness Premiership."
The new backroom team also features Bob Stewart who continues his role as Director of Sports Medicine. Stewart, formerly the physiotherapist for the Scottish Rugby Union Team and Glasgow Warriors, brings exceptional experience to the position. He was the Official Team Physiotherapist for the 2005 British and Irish Lions Tour and the Scotland Physiotherapist for the IRB World Cup in 2003. Stewart will continue to work alongside club physiotherapists Ben MacDonald and Mike Lancaster.
Strength & Conditioning Co-ordinator Keir Hansen also moves into his second full season at Sixways. Hansen previously worked for five successful years with the New Zealand Warriors Rugby League team and alongside Warriors Conditioner Stuart Pickering will be working with the new squad for pre-season training from mid-June. Analyst Mike Hall will continue to provide his expertise and Tony Boddy remains as Team Manager.