A buffet can be either a sideboard (a flat-topped piece of furniture with cupboards and drawers, used for storing crockery, glasses, and table linen) or a system of serving meals in which food is placed in a public area where the diners serve themselves.^[1] A form of service à la française, buffets are offered at various places including hotels, restaurants, and many social events. Buffet restaurants normally offer all-you-can-eat food for a set price, but some measure prices by weight or by number of dishes. Buffets usually have some hot dishes, so the term cold buffet (see Smörgåsbord) has been developed to describe formats lacking hot food. Hot or cold buffets usually involve dishware and utensils, but a finger buffet is an array of foods that are designed to be small and easily consumed only by hand, such as cupcakes, slices of pizza, foods on cocktail sticks, etc.

The essential feature of the various buffet formats is that the diners can directly view the food and immediately select which dishes they wish to consume, and usually also can decide how much food they take. Buffets are effective for serving large numbers of people at once, and are often seen in institutional settings, business conventions, or large parties.

In the 19th century, supper, a lighter meal some hours after the main dinner, was sometimes served as a buffet (and so called), especially late at night at grand balls, where not everyone present eats at the same time, or in the same quantity. Even in a very large building, at a large ball there might not be enough space to seat all guests at the same time, or servants to serve them in the manner required by the prevailing customs. A large cooked English breakfast with various choices was also very often routinely served this way, for similar reasons. Even when many servants were on hand, there might be an element of self-service. The term buffet originally referred to the French sideboard furniture where the food was placed, but eventually became applied to the serving format.

At balls, the "buffet" was also where drinks were obtained, either by circulating footmen supplying orders from guests, but often by the male guests. During the Victorian period, it became usual for guests to have to eat standing up. In fact John Conrade Cooke's cookbook Cookery and Confectionery, (London: 1824) says it was already "the present fashion". In a report on a ball in 1904, a departure from "the usual stand-up buffet supper", with parties being able to reserve tables, was praised.

Scandinavians like to claim that the buffet table originates from the brännvinsbord (Swedish schnapps, or shot of alcoholic beverage) table from the middle of 16th century. This custom had its prime during the early 18th century. The smörgåsbord buffet did not increase in popularity until the expansion of the railroads throughout Europe.

The smörgåsbord table was originally a meal where guests gathered before dinner for a pre-dinner drink, and was not part of the formal dinner that followed. The smörgåsbord buffet was often held in separate rooms for men and women before the dinner was served.

Smörgåsbord became internationally known as "smorgasbord" at the 1939 New York World's Fair exhibition, as the Swedes had to invent a new way of showcasing the best of Swedish food to large numbers of visitors.