Barbecue sauce is a condiment used to baste, glaze, or serve alongside grilled or smoked meat, built from a tomato base (ketchup or puree), vinegar, a sweetener (brown sugar, molasses, or honey), and spices such as garlic, onion, paprika, and chili powder. It differs from a barbecue rub, which is a dry spice blend applied before cooking rather than a liquid sauce.
The tomato-based style associated with American barbecue developed in the South, with regional variations: Kansas City sauce is thick, sweet, and tomato-heavy; Carolina sauce is thinner and vinegar- or mustard-based; and Alabama white sauce is mayonnaise-based rather than tomato-based.
Outside the U.S., similarly named sauces vary widely - Korean barbecue sauces are often gochujang-based, and Japanese-style versions resemble teriyaki (soy sauce, mirin, sugar).
Beyond basting meat, barbecue sauce is used as a dip, a sandwich condiment, and an ingredient in baked beans, coleslaw dressing, or meatloaf.