Lululemon has hit Ross Stores Inc. and one of its suppliers with a lawsuit claiming that the discount retailer has been selling shabby knockoffs of the company’s high-end yoga pants in stores in California.

Vancouver, Canada-based Lululemon Athletica Canada Inc. filed suit Thursday in the U.S. District Court for the Northern District of California bringing claims of trademark infringement and counterfeiting as well as state and federal claims of unfair competition against Ross Stores and IOPA Inc., a Los Angeles-based distributor of athletic apparel.