Victoria Beckham, Geri Halliwell, Emma Bunton, Mel B and Mel C will sell the famous costumes to coincide with the launch of new West End musical Viva Forever.
"I've got all my costumes still. I can't wait for Harper to grow a little so she can have some. But the rest I'd like to put up for charity, I think it would be a fantastic thing to do," Beckham told The Mirror.
"Everything we did at the time was great, it really was great. We watched a little video Geri put together and I think we were nearly all brought to tears."
Mel C will donate her trademark Adidas tracksuits and crop tops, while Bunton is giving away a babydoll shift dress.
Halliwell's famous Union Jack dress is already on display at the Hard Rock Cafe in Las Vegas.
The auction, Beckham's idea, will raise funds for Save The Children and Children in Need.
Bunton recently said that the Spice Girls musical is especially for the fans who have supported the group through the years.
Watch the Spice Girls talk about Viva Forever below:
Photo gallery - Spice Girls through the years:
Copyright: Rex Features