The Scot will lead the trip to South Africa next year for what will be his fourth spell in charge.
"I'm delighted to be here," McGeechan said. "It's an honour and privilege to get the opportunity to coach the Lions again.
"The Lions have always been so important to me. The Lions are special and unique. You can't compare them to anything else you do as a player or coach.
"Because they're so unique the preparation has to be unique. Ten games in eight weeks is a unique challenge.
"I believe you need a very tight squad. All preparations for 2009 will be about one group working very closely together.
"The fact it's against the world champions Springboks also makes it a massive challenge.
"I'm looking forward to working with Gerald Davies, the team manager. This will be a partnership. My responsibility will be the rugby and that will be my sole focus.
"The tradition of the Lions is important to making sure the Lions have a fighting chance of succeeding in South Africa.
"I will continue coaching at Wasps as it's important I'm hands on there. The arrangement does allow me to be flexible and the club are happy with that."
McGeechan revealed he will be assembling his back room staff as soon as possible.
He said: "Gerald and I will spend some time together and talk things through.
"I hope that over the next two months the management structure will be in place. From now we'll be working very hard in that respect."
The Lions have 10 matches scheduled in South Africa, including Tests against the Springboks in Durban, Pretoria and Johannesburg between June 20 and July 4.
Other fixtures include appointments with the Emerging Springboks, Western Province and the Sharks and the tour opens on May 30 against a Highveld XV in Rustenburg.