The hamburger chain says it will offer the Veggie Slider for 99 cents each for a limited time at its 400 locations in 12 states.
The sliders range between 150 and 270 calories, with customers able to choose from three sauces — honey mustard, ranch and sweet Thai. Regular beef sliders range between 140 and 220 calories, depending on the topping, according to White Castle's website.
The chain, based in Columbus, Ohio, says the sliders are made with Dr. Praeger's veggie patty and include carrots, zucchini, peas and spinach. A spokesman, Todd Hutchins, said they were tested this past summer in New York and New Jersey.
White Castle Vice-President Jamie Richardson said in a statement the company is committed to "listening to our customers and keeping up with changing tastes" with new menu items.
A petition on Change.org asking McDonald's to offer a veggie burger had more than 107,000 supporters. Chipotle has also been rolling out a "Sofritas" vegan tofu topping for its burritos and bowls, and executives have noted the offering has appeal even for meat eaters.