National Cheeseburger Day is celebrated annually on September 18. In 2025, it falls on a Thursday. This day honors the delicious classic cheeseburger and is often marked by free or discounted cheeseburgers at various restaurants and special deals nationwide. The day also pays tribute to Lionel Sternberger, credited with inventing the cheeseburger in the 1920s by adding a slice of cheese to a hamburger patty. Many fast-food franchises and burger joints celebrate this day with special promotions.
