A double-decker bus is a bus that has two storeys or 'decks'. Global usage of this type of bus is more common in outer touring than in its intra-urban transportion role. Double-decker buses are also commonly found in certain parts of Europe, Asia, and former British colonies and protectorates (Hong Kong, Singapore, etc.).

Almost all double-deckers have a single, rigid chassis. Some double-deckers are used solely for sight-seeing tours; as William Ewart Gladstone observed, "...the way to see London is from the top of a 'bus". (Gladstone was referring to London's once ubiquitous double-deck horse drawn omnibuses, rather than a motor bus).

Cities listed here use double-decker buses as part of their regular mass transit fleet. Cities with only tourist and sightseeing double-decker buses are excluded.

Double-decker buses are in common use throughout the United Kingdom, and have been favoured over articulated buses by many operators because of the shorter length of double-deckers, and less need to have standing capacity. The majority of double decker buses in the UK are between 9.5 metres (31 ft 2 in) and 11.0 metres (36 ft 1 in) long, the latter being more common since the mid-1990s, though there are three-axle 12 metres (40 foot) models in service with some operators. Double-decker coaches in the UK have traditionally been 12.0 metres in length, though many newer models are about 13.75 metres (45 ft 1 in). The maximum permissible length of a rigid double-decker bus and coach in the UK is 15.0 metres (49 ft 3 in), and although there are no theoretical restrictions on height, coaches are normally built to 4.38 metres (14 ft 4 in) high, while 'highbridge' buses are normally about 20 centimetres (8 in) taller. Articulated double-deckers are also allowed at a maximum length of 18.75 metres (61 ft 6 in).

A double-decker is a vehicle that has two levels for passengers or cargo, one deck above the other. Such vehicles include:

A double-decker may also refer to:

Gabriel J. Iglecias (born July 15, 1976), known professionally as Gabriel Iglesias, is an American standup comedian and actor, known for his shows I'm Not Fat… I’m Fluffy and Hot & Fluffy. He employs storytelling, effected voices and sound effects in his act, whose other trademarks include references to his weight and his use of Hawaiian shirts. He has been called a "comedy genius" by Hector Saldaña of the San Antonio Express-News.

Gabriel Iglesias was born Gabriel J. Iglecias in San Diego, California. He is of Mexican-American heritage. His mother placed a letter "c" in his surname in retaliation for his father's absence during his birth, though he does not use this spelling in his every day life, preferring to use the one with the "s". He and his mother lived in Riverside, Corona, Santa Ana, Baldwin Park and Compton before settling in Long Beach, where Iglesias spent most of his life growing up.

Before going into comedy, Iglesias worked for a cell phone company in Los Angeles. Although his family urged him to remain in that job for its financial security, he insisted on trying his hand at comedy. When maintaining both occupations proved too difficult to handle, he decided to take the risk of doing comedy full time, against the advice of his mother, who cautioned him against such a move. Iglesias nonetheless left the phone company, which eventually resulted in his being evicted from his home and losing his car. Despite this, he persisted with comedy.