The Big Mac is a hamburger sold by the international fast food restaurant chain McDonald's. It was introduced in the Greater Pittsburgh area in 1967 and across the United States in 1968. It is one of the company's flagship products and signature dishes. The Big Mac contains two beef patties, cheese, shredded lettuce, pickles, minced onions, and a Thousand Island-type dressing advertised as "special sauce", on a three-slice sesame-seed bun.

Thousand Island dressing is an American salad dressing and condiment based on mayonnaise that can include olive oil, lemon juice, orange juice, paprika, Worcestershire sauce, mustard, vinegar, cream, chili sauce, tomato purée, and ketchup or Tabasco sauce. It also typically contains finely chopped ingredients, which can include pickles, onions, bell peppers, green olives, hard-boiled egg, parsley, pimento, chives, garlic, or chopped nuts.