The Pug is a small but robust dog about 25–28 cm tall and with an average weight of 15 to 25 lb (7 to 11 kg). They are said to have been bred to be royal companions. The Pug is a very sociable dog, as well as being extremely smart and quite stubborn. Their appearance is characterized by a flat, wrinkled face, compact body, and curled tail. Pugs have three color variations: fawn with a black mask and ears, entirely black, or silver. Silver is, however, only mentionable in an historical context, as there are no known extant silver pugs (Additionally, the AKC now only recognizes pugs as Fawn or Black). The pug is popular as a house pet, as it requires little exercise and is easy to groom. They are also compatible with most children and other animals.

Because they have extremely short snouts, some pugs easily scratch their corneas, and can develop breathing problems. They are also prone to skin infections if the crevices in their face are not kept clean. Teeth and mouth problems are also caused by the flat faces. Pugs are prone to obesity, and can reach unhealthy weights. Pugs can also suffer from a fatal disease specific to their breed called Pug Dog Encephalitis (PDE), which is a chronic form of Granulomatous Meningoencephalitis (GME) (an inflammation of the brain). PDE is suspected to be an inherited disease in pugs and research is ongoing. The disease progresses rapidly, and there is currently no known cause or cure.