Walmart Inc. and its cashiers won approval for a settlement in which the retailer will pay $65 million and begin offering seats to those workers.

It is the largest settlement ever under a lawsuit filed under California’s unique Private Attorneys General Act, which lets individuals file labor enforcement actions on the state’s behalf and collect one quarter of the penalties, the parties said when they submitted the deal for approval.

The settlement covers about 99,000 class members who allege the retailer failed to comply with a California requirement to provide suitable seating when the nature of the work allows it....