Soursop is the fruit of Annona muricata, a broadleaf, flowering, evergreen tree. It is native to the tropical regions of the Americas and the Caribbean and is widely propagated. It is in the same genus, Annona, as cherimoya and is in the Annonaceae family.

The Annonaceae are a family of flowering plants consisting of trees, shrubs, or rarely lianas commonly known as the custard apple family or soursop family. With 108 accepted genera and about 2400 known species, it is the largest family in the Magnoliales. Several genera produce edible fruit, most notably Annona, Anonidium, Asimina, Rollinia, and Uvaria. Its type genus is Annona. The family is concentrated in the tropics, with few species found in temperate regions. About 900 species are Neotropical, 450 are Afrotropical, and the remaining are Indomalayan.