The Football Association announced on Sunday morning the Manchester United winger would lead the hosts' bid for gold.
The 38-year-old is one of the three over-age players in Stuart Pearce's squad for the Games, alongside Micah Richards and Craig Bellamy.
Giggs said: "Obviously I have experience and there are a lot of younger players in this squad, as captain hopefully I can pass that on to the younger players."
Stuart Pearce added: "I think Ryan is the standout captain amongst the group. He has got the respect of all the members of the group and I am quite looking forward to working with him and alongside him."
Despite never having played in a major international tournament with Wales, he has won 12 Premier League titles, five FA Cups and two Champions League crowns. He also won 64 caps for Wales before retiring from international football in 2007.
Giggs, Richards and Bellamy were picked ahead of David Beckham whose non-selection provoked a lot of debate.
Giggs will lead out Team GB for the first time when they face Brazil at the Riverside Stadium on Friday, July 20.