The beagle is a breed of small hound that is similar in appearance to the much larger foxhound. The beagle is a scent hound, developed primarily for hunting hare (beagling). Possessing a great sense of smell and superior tracking instincts, the beagle is the primary breed used as detection dogs for prohibited agricultural imports and foodstuffs in quarantine around the world. The beagle is intelligent. It is a popular pet due to its size, good temper, and a lack of inherited health problems.

The modern breed was developed in Great Britain around the 1830s from several breeds, including the Talbot Hound, the North Country Beagle, the Southern Hound, and possibly the Harrier.

Beagles have been depicted in popular culture since Elizabethan times in literature and paintings, and more recently in film, television, and comic books. Snoopy of the comic strip Peanuts has been called "the world's most famous beagle".
 

The beagle has an even temper and gentle disposition. Described in several breed standards as "merry", they are amiable and typically neither aggressive nor timid, although this depends on the individual. They enjoy company, and although they may initially be standoffish with strangers, they are easily won over. They make poor guard dogs for this reason, although their tendency to bark or howl when confronted with the unfamiliar makes them good watch dogs. In a 1985 study conducted by Ben and Lynette Hart, the beagle was given the highest excitability rating, along with the Yorkshire Terrier, Cairn Terrier, Miniature Schnauzer, West Highland White Terrier, and Fox Terrier.

Beagles are intelligent but, as a result of being bred for the long chase, are single-minded and determined, which can make them hard to train. They can be difficult to recall once they have picked up a scent, and are easily distracted by smells around them. They do not generally feature in obedience trials; while they are alert, respond well to food-reward training, and are eager to please, they are easily bored or distracted. They are ranked 72nd in Stanley Coren's The Intelligence of Dogs, as Coren places them among the group with the lowest degree of working/obedience intelligence. Coren's scale, however, does not assess understanding, independence, or creativity.