Why did Lululemon sue Costco? All about the ‘dupes’ lawsuit

Renowned apparel brand Lululemon has reportedly sued the popular membership-based warehouse club Costco. According to a People report, Lululemon filed a lawsuit in federal court in California on June 27, 2025.

The legal dispute stems from Lululemon’s claim that Costco sold imitations of its signature apparel under the Kirkland brand.

People obtained the lawsuit documents submitted to the court. Lululemon alleged Kirkland “unlawfully traded” on its brand and misled loyal customers.

As People cited, the global clothing brand accused Costco of misusing their original products,’

"reputation, goodwill and sweat equity by selling unauthorized and unlicensed apparel employing knockoff, infringing versions"

The company accused Costco of profiting from cheaper imitations that capitalized on Lululemon’s popularity.

Everything we know about Lululemon's lawsuit against Costco

The clothing brand began its journey decades ago. Since 1998, it has established its name firmly in the market and has also garnered a loyal customer base by catering to their needs with quality products.

Lululemon described itself as a “path-breaking” brand that invests heavily in developing and protecting its innovations.

”substantial effort and resources to develop, promote, and protect its brands and innovations."

Claiming that Costco copied the feel and design of their popular products, such as ABC pants, sweatshirts, and scuba hoodies, the plaintiff named these items their “pioneering products.”

The lawsuit, filed as an intellectual property enforcement action, targets retailers that Lululemon claims “copy rather than compete.”

"retailers who have chosen to copy rather than compete."

In the detailed official lawsuit, the apparel label shared more about Costco’s dupes and conveyed,

"Costco has unlawfully traded upon Plaintiffs' reputation, goodwill and sweat equity by selling unauthorized and unlicensed apparel employing knockoff, infringing versions of Plaintiffs' well-known trade dress and design patents (the 'Infringing Products') and to recover fully for the monetary damages and significant harm to lululemon’s brands and reputation caused by Defendant."

The plaintiff also called Costco’s similar products “knockoffs” or “dupes.” In addition to these accusations, it also spoke about a hashtag #LululemonDupes. Allegedly, social media influencers post their content on “these copycat products” with this hashtag.

Later, the claimant also stated in the lawsuit,

"The Infringing Products create an improper association with Plaintiffs’ authentic products."

The petitioner also noted that the dupes

"are difficult to distinguish from authentic Lululemon products."

Lululemon argued that Costco’s similar products confuse customers and damage its intellectual property rights and reputation.

It also addresses the fact that Costco’s knockoffs undermine its premium image and market.

The official lawsuit filed in the court on Friday also includes the plaintiff pointing out,

"One of the purposes of selling 'dupes' is to confuse consumers at the point-of-sale and/or observers post-sale into believing that the 'dupes' are Plaintiffs’ authentic product when they are not."

It further added,

"As a direct and proximate result of the foregoing acts, Plaintiffs have suffered and will continue to suffer significant injuries in an amount to be determined at trial."

The label blamed Costco for creating dupes of these products, as People confirmed:

• Danskin Ladies Half-Zip Hoodie
• Danskin Half-Zip Pullover
• Hi-Tec Men’s Scuba Full Zip
• Jockey Ladies Yoga Jacket
• Kirkland 5 Pocket Performance Pant
• Spyder Women’s Yoga Jacket

Lululemon seeks full compensation for the alleged harm.