

Smashburger's Triple Double (left) and In-N-Out's Double Double. (Photos courtesy of In-N-Out and Smashburger)

In-N-Out has filed a trademark infringement lawsuit against Denver-based Smashburger over the Colorado chain's new Smashburger "Triple Double" menu item. In In-N-Out's view, the Triple Double is infringing on the Southern California-based burger chain's famed Double Double territory.

“Smashburger’s use of the Triple Double and Smashburger Triple Double marks is likely to confuse and mislead the consuming public, and injure In-N-Out, by causing consumers to believe incorrectly that Smashburger’s products originate from or are authorized by In-N-Out,” the lawsuit, which was filed Monday, states, according to the Orange County Register.

In-N-Out has continuously used and held trademarks "in connection with hamburger sandwiches in interstate commerce" for both the Double Double and the Triple Triple since the mid-1960s, according to the lawsuit.

Smashburger, which was founded in 2007, expanded to Orange County five years ago and now has three locations there, according to the Register. There are also Smashburger outposts in Culver City, at L.A. Live, and at Universal Studios, among other L.A.-area locations.

The Triple Double, which was introduced last month, has two patties and three layers of cheese. In-N-Out's Double Double and Triple Triple have two patties and two layers of cheese, and three patties and three layers of cheese, respectively.