Boisduvallia
Calylophus
Camissonia
Chamerion
Circaea
Clarkia
Epilobium
Eucharidium
Fuchsia
Gaura
Gayophytum
Gongylocarpus
Hauya
Hemifuchsia
Heterogaura
Isnardia
Jussiaea
Lopezia
Ludwigia
Oenothera
Stenosiphon
Xylonagra
Zauschneria

The Onagraceae or Willowherb family (or Evening Primose family) is a family of flowering plants. The family includes about 640-650 species of herbs, shrubs, and trees in 20-24 genera. The family is widespread, on every continent from boreal to tropical regions.

The family includes a number of popular garden plants, including evening primroses (Oenothera) and fuchsias (Fuchsia). Some, particularly the willowherbs (Epilobium) are common weeds in gardens, e.g. Fireweed.

The family is characterised by flowers with usually four sepals and petals; in some genera (e.g. Fuchsia), the sepals are as brightly coloured as the petals, giving the impression of a flower with eight petals. The seeds are very small, in some genera (e.g. Epilobium) with a tuft of down and wind-dispersed, in others (e.g. Fuchsia), in a juicy berry and dispersed by birds. The leaves are commonly opposite or whorled, but are spirally arranged in some species; in most, they are simple and lanceolate in shape.

The family is named after the genus Onagra (now known as Oenothera) in 1836 by J. Lindley in the second edition of Nat. Syst. Bot.