In a closely watched case, the Supreme Court decided in Wal-Mart Stores, Inc. v. Dukes, No. 10-277 (U.S. June 20, 2011), that a gender discrimination lawsuit brought by three named plaintiffs on behalf of 1.5 million current and former Wal-Mart employees could not proceed as a class action. Apart from the noteworthy result of preventing the largest employment discrimination lawsuit in United States history from going forward, the case is important for the effects it will have on a broad range of class actions and employment discrimination suits. The Wal-Mart decision may make it more difficult for many types of class-based suits to proceed.

The named plaintiffs in the case alleged that they had been denied equal pay and promotions because of their sex in violation of Title VII of the Civil Right Act of 1964. The plaintiffs maintained that Wal-Mart's policy of allowing local managers to have discretion over pay and promotions, along with an allegedly strong and uniform corporate culture that permitted bias against women to infect decision-making, combined to cause discrimination against both the plaintiffs and all other women employed by Wal-Mart. The plaintiffs sought injunctive and declaratory relief as well as backpay.

At the plaintiffs' request, lower courts certified the case to proceed as a class action on behalf of all women who had worked for Wal-Mart since the commencement of the case. The Supreme Court reversed the lower courts' class certification order for several reasons.