In its 6-5 ruling, the 9th Circuit U.S. Court of Appeals said the world's largest private employer will have to face charges that it pays women less than men for the same jobs and that female employees receive fewer promotions and have to wait longer for those promotions than male counterparts.
The retailer has fiercely fought the lawsuit since it was first filed by six women in federal court in San Francisco in 2001 and said it would appeal the decision to the U.S. Supreme Court.
The ruling "opens up every company in America that has employees to class actions like this," said Theodore Boutrous, the company's lead lawyer on the largest gender bias class action in U.S. history.
The appeals court upheld a lower court ruling allowing the lawsuit to go forward as a class action, which attorneys for the Wal-Mart employees said encompasses more than 1 million women. Wal-Mart disputes that figure and asserts fewer than 500,000 women are covered by the decision Monday.
Either way, the company could lose billions of dollars if it is found liable and required to fork over back pay to the affected women.