A Smashburger product that is posting double-digit sales increases for the brand has caught the attention of a competitor.

In-N-Out has filed a federal trademark lawsuit against Smashburger and its “Triple Double Burger,” claiming it’s too similar to its popular “Double-Double” and “Triple Triple” burgers. In the suit, In-N-Out argues that Smashburger’s Triple Double infringes on its trademark and dilutes its distinctive quality.

READ MORE: What is the secret to In-N-Out’s cult following?

According to the filing, In-N-Out has registered trademarks for its Double-Double since 1963 and Triple Triple since 1966. The suit claims that the brand believes there is “a likelihood of consumer confusion because actual and prospective customers are likely to believe that In-N-Out has approved or licensed Smashburger’s use of its marks, or that In-N-Out is somehow affiliated or connected with Smashburger or its services.”

Smashburger launched its Triple Double Burger in June to celebrate its 10th anniversary. It contains two patties and three layers of melted cheese. In-N-Out’s Double-Double contains two cheese slices and two beef patties, while its Triple Triple has three patties with three slices of cheese.  

“We named it the Smashburger Triple Double, which has really resonated with consumers,” Smashburger co-founder and CEO Tom Ryan said in a statement. “Frankly, we are flattered by the attention In-N-Out has given our Smashburger Triple Double. (The) burger is clearly popular with our customers and is not comparable to any In-N-Out menu offering.”

Burgers, Fast Casual, News, In-N-Out Burger, Smashburger