The white, puff-ball blouse and blue gingham pinafore, which the star wore to play Dorothy in the 1939 film, sold for $480,000 (£300,000) when it went under the hammer this week (ends11Nov12).
Garland's outfit is one of the most famous costumes in cinema history and although several identical ensembles were made for the movie, it was the only one to have been seen on film and the only complete version to have survived intact.
Other items which went under the hammer at the Julien's Auctions sale in Beverly Hills, California included a pair of sunglasses famously worn by John Belushi in 1980 movie The Blues Brothers, which sold for $16,640 (£10,400).
A dress seen on Julie Andrews in The Sound of Music made $38,400 (£24,000) and a purple skirt worn by Marilyn Monroe in River of No Return sold for $50,000 (£31,250). A racing jacket owned by Steve McQueen also went for $50,000 (£31,250).