Watch out, McDonald's and Starbucks. 

Chick-fil-A, the fast food chain whose signature fried chicken sandwich isn't its most popular menu item (that honor goes to its waffle fries), is taking over the country. It's set to become the third-largest U.S. restaurant by sales by the end of 2018 according to Kalinowski Equity Research—a spot currently held by Subway (McDonald's and Starbucks are the reigning champs).

waffle fries
Credit: © quadxeon/Getty Images

The friendly-yet-controversial fried chicken franchise has been in expansion overdrive since nabbing the number seven slot on the same list back in 2017. Chick-fil-A’s sales are expected to grow as much as 15 percent to $10 billion on top of 14.2 percent growth last year, Business Insider reports, citing Kalinowski's data. Their closest competitor is currently Domino's, whose sales grew by roughly 12% in 2018. "We have long pointed out that Chick-fil-A is the restaurant competitor with which McDonald's...should most concern itself," Kalinowski wrote, "and by extension, investors should, too." (Although, here we should note that if Chick-fil-A were to continue growing at the same rate, and McDonald's stood still, it would take them 21 years to leapfrog over Mickey D's—a fact Restaurant Business originally pointed out.)

Chick-fil-A has been casting a wide net when it comes to ways to expand the business—some more inventive than others. This March, Chick-fil-A opened its largest-ever outpost, in New York City (the 12,000-square-foot space includes a rooftop dining area and floor-to-ceiling windows). And over the summer, the chain tested out meal kits at some of its Atlanta locations—an interesting idea in theory, but making your own fast food kind of takes the "fast" part out of it, no? One thing that Chick-fil-A hasn't done is add menu items: the company expects to finish 2018 without a new offering (well, without a nationwide new offering) for the first time in years.