The house sparrow (Passer domesticus) is a member of the sparrow family Passeridae. This small bird typically measures around 16 cm (6.3 in) in length and weighs between 24–39.5 g (0.85–1.39 oz). The species exhibits sexual dimorphism, with females and young birds displaying pale brown and grey plumage, while males are characterized by more vibrant black, white, and brown markings.

Males can be identified by their bright black, white, and brown markings, with a distinctive black bib, white cheeks, and a grey crown. Females lack the striking head patterns of males and are predominantly buffish with softer coloration. Juveniles resemble adult females but are generally paler with less defined markings.

The house sparrow is highly adaptable and can thrive in both urban and rural environments. It is commonly found in close association with human habitation and avoids dense forests, grasslands, polar regions, and deserts far from human development.

Native to Europe, the Mediterranean Basin, and much of Asia, the house sparrow has been introduced to various regions worldwide, including parts of Australasia, Africa, and the Americas, making it one of the most widely distributed wild birds.

House sparrows are social birds, often seen in flocks. They exhibit a range of behaviors, including dust or water bathing and communal roosting. Males are known to be territorial around their nesting sites.

The house sparrow's vocalizations are predominantly variations of a simple chirping call. Males may sing or give an "ecstatic call" during the breeding season, and the species uses a variety of calls for different social interactions.

House sparrows are generally monogamous and may mate for life. They can breed in the season following their hatching and often produce multiple clutches per year, with each clutch containing up to five eggs. Nest sites are varied, with a preference for cavities.

An opportunistic feeder, the house sparrow's diet consists mainly of seeds from grains and weeds, but it also consumes insects and other invertebrates, especially during the breeding season when feeding young.