Christie's director Nicolette Tomkinson said Wednesday's sale price, more than double the highest estimate, reflected the gown's significance in the history of film and fashion.
Taylor wore the cream-coloured, seed pearl-encrusted satin dress - complete with waist-cinching built-in corset - to the first of her eight weddings in May 1950.
Hundreds of guests including Gene Kelly, Ginger Rogers and Fred Astaire turned up, and studio MGM boasted that "more stars than there are in heaven" attended.
Taylor and Hilton divorced months later, and the actress went on to wed seven more times.
She died in 2011, aged 79.
