Nicole Trombley of Snohomish County said Amanda's Bridal Boutique in Redmond, Wash., tried to pass off the used, ill-fitting gown as new.
The bride-to-be opened the dress bag a week before her wedding to find the dress had "stains, rips, frays" and pieces missing, the lawsuit said.
The designers of the dress confirmed it had not sold any dresses to the boutique in the past year, the Seattle Post-Intelligencer reported Thursday.
The boutique agreed to refund Trombley her money and allowed her to take any dress from the shop for free for her wedding, the lawsuit said.
The amount Trombley seeks in damages was not reported by the online newspaper.