The offer comes amid celebrations of the fast-food chain's 15th annual Cow Appreciation Day, during which the company commemorates its "Eat Mor Chikin" cows.
Customers who visit one of the restaurants' 2,400 locations across the U.S. dressed up like a cow are eligible to receive a free entrée from opening until 7 p.m.
Cow costumes, per Chick-fil-A, are defined as anything "cow-like." That includes spotted accessories, a T-shirt with black and white spots, or "a cow hat or mask, etc."
Despite serving chicken dishes, Chick-fil-A is widely known for its cow mascots. The company said in a news release that 2019's Cow Appreciation Day marks the chain's 24th anniversary of its "Eat More Chikin" cows marketing campaign.
Chick-fil-A said that during last year's appreciation day, 1.95 million customers dressed up like cows for a free meal.
The company's senior vice president and chief marketing officer, Jon Bridges, said in a statement that Chick-fil-A is "grateful for our customers’ enthusiasm toward this fun annual tradition."