A hamburger (also called a hamburger sandwich, burger or hamburg) is a sandwich consisting of a cooked patty of ground meat (usually beef, but occasionally pork or a combination of meats) usually placed inside a sliced bread roll. Hamburgers are often served with lettuce, bacon, tomato, onion, pickles, cheese and condiments such as mustard, mayonnaise, ketchup and relish.

The term "burger", can also be applied to the meat patty on its own, especially in the UK where the term "patty" is rarely used. The term may be prefixed with the type of meat as in "beef burger".