Like the hummingbirds, sunbirds are strongly sexually dimorphic, with the males usually brilliantly plumaged in iridescent colours.

Sunbirds have long thin down-curved bills and brush-tipped tubular tongues, both adaptations to their nectar feeding.

They are typically larger than the other sunbirds, with drab brown plumage that is the same for both sexes, and long, down-curved beaks.

[4] The sunbirds and spiderhunters occupy a wide range of habitats, with a majority of species being found in primary rainforest, but other habitats used by the family including disturbed secondary forest, open woodland, open scrub and savannah, coastal scrub and alpine forest.

Some species have readily adapted to human modified landscapes such as plantations, gardens and agricultural land.

[4] Sunbird are active diurnal birds that generally occur in pairs or occasionally in small family groups.

Where species, like the buff-throated sunbird, breed in the dry season, it is thought to be associated with the flowering of favoured food plants.

[8] The nests of sunbirds are generally purse-shaped, enclosed, suspended from thin branches with generous use of spiderweb.

[11][12] Sunbirds are critical pollinators for many iconic African plants, including proteas,[13] aloes,[14] Erica,[12] Erythrina coral trees,[10] and bird-of-paradise flowers.

[15] Specialization on sunbirds vs other pollinators is thought to have contributed to plant speciation, including the exceptionally high floral diversity in southern Africa.

Most species are fairly resistant to changes in habitat, and while attractive the family is not sought after by the cagebird trade, as they have what is considered an unpleasant song and are tricky to keep alive.

There are a few negative interactions, for example the scarlet-chested sunbird is considered a pest in cocoa plantations as it spreads parasitic mistletoes.