The fast food chain known for its “Roast Beef” sandwiches is Arby’s. Roast beef was central to the chain’s identity from its first restaurant and remains its signature association.
Arby’s was founded in 1964 by brothers Forrest and Leroy Raffel, who had operated a restaurant-equipment business. Instead of competing directly with hamburger chains, they built a concept around sliced roast beef served in a fast-food format. The name Arby’s is commonly explained as a reference to the Raffel brothers—“R.B.”—rather than simply an abbreviation for roast beef.
The original menu focused on roast beef sandwiches, curly fries, and shakes. Over time, Arby’s added turkey, chicken, brisket, corned beef, Reubens, Market Fresh sandwiches, and limited-time game meats. Those additions sometimes make people forget that roast beef is the chain’s defining product.
Arby’s is also distinct from hamburger-focused chains such as Wendy’s, Burger King, and McDonald’s. Its branding and menu have broadened, but the roast beef sandwich remains the clearest answer to this question.