32-year old Tandy, from Tonmawr, will be assisted by current Forwards Coach Jonathan Humphreys, with the full make-up of his coaching team to be confirmed.
An Ospreys 'original', Tandy has been a part of the Ospreys set-up since the inception of regional rugby, his debut coming in September 2003 against Leinster at Donnybrook. In total, he played 102 times for the Ospreys, scoring 10 tries, with his final appearance coming against Edinburgh in March 2010.
The former back-rower cut his coaching teeth within the Ospreys age-grade set-up, taking the U16 squad to the WRU Regional Age Grade Championship before becoming Head Coach at Bridgend Ravens, where he led them back into the Welsh Premiership last season at the first attempt.
While at Bridgend, he has combined his time with a coaching role at the Ospreys, first working with the B group of players at the region, and then as Technical Coach. During this season's LV= Cup campaign, he stepped up as Acting Head Coach.
Speaking about his new post, Tandy said:
"This is an excellent opportunity for me and I'm really excited about the challenges ahead. Clearly there's an air of expectation on whoever is in charge at the Ospreys, but having been here since the very beginning I know what to expect.
"The Ospreys are my home region and I was lucky enough to be able to wear the shirt on 102 occasions. When I was still playing I worked hard to develop as a coach and I've been fortunate to be at a region that values coach development as it's allowed me to get some fantastic experience within the Ospreys and at Bridgend.
"I enjoyed taking charge of the team during the LV= Cup and I'm confident in my ability to be able to make a success of this opportunity. It's a tough job, but I share the Ospreys ambitions and want to be able to play my part in us achieving those ambitions.
"Initially, my focus will be on attempting to finish this season on a high. We are in a good position in the PRO12 with eight games to go, and the target is for us to achieve a home semi-final. We want to maintain both our position as the leading Welsh region and our proud record in the competition, which I was fortunate enough to win three times as a player. I know I've got the support of the players, staff and directors at the Ospreys and hope that the fans will also be behind me, starting on Friday night."
Andrew Hore, Chief Operations Officer, Ospreys Rugby commented:
"We are delighted to be able to confirm Steve's appointment as Head Coach. He is a true stalwart of the region having served us so well as a player, and is a straight talker and natural leader who has already enjoyed success as an age-grade and club coach.
"As a business, we've had the foresight to invest heavily in development structures in order to make us more sustainable, and Steve has benefited from the coaching pathway we've put in place at the region, working his way through the system. He is still young, but sometimes as is the case with players, if they've got the ability then you have to give them the opportunity.
"He's a forward thinker who has his own ideas about how to do things. I know he is excited about the future for the Ospreys, and as a business, we share that excitement. We believe he will be a success in this role, not only helping to take the Ospreys onto another level, but to help with the continued development of other coaches in the region.
"This is an exciting time for Steve, and for the Ospreys, and with the push for the PRO12 semi-finals over the coming weeks, we have everything to play for."
Following Steve's appointment he will relinquish his duties at Bridgend, where Ravens flanker and current WRU/Ospreys Regional Community Manager, Ben Rose, will step up as Interim Head Coach until the end of the season, assisted by Backs Coach Craig Warlow and Forwards Coach, Richard Lancaster.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland