Three of the gowns were made by British dressmaker Catherine Walker, Diana's favourite designer and close personal friend, as well as one by Caroline Charles and another by Zandra Rhodes.
The Catherine Walker dresses all fetched within or just above their estimated price of between USD 60,000 and USD 80,000.
An off-the-shoulder petal pink gown embellished with bands of simulated pearls, faceted glass and beadwork went for USD 75,000.
Also on offer was a strapless ivory silk crepe dress which went for USD 76,800, while a chartreuse silk georgette gown worn by Diana in 1993 fetched USD 81,250.
The Caroline Charles burgundy wool coat dress was the surprise of the five, going for USD 125,000 -- easily beating its pre-sale estimate of USD 20-40,000.
The dresses went under the hammer, along with other Diana-related items, Friday evening at Julien's Auctions in Beverly Hills.