The genus Geospiza was introduced in 1837 by the English ornithologist John Gould with the large ground finch as the type species.

[1][2] The genus name derives from the two Ancient Greek words γῆ (gê), meaning "earth", and σπίζα (spíza), a catch-all term for finch-like birds.

[3][4] The member of the genus form part of a group collectively known as Darwin's finches.

[5] Although traditionally placed with the buntings and New World sparrows in the family Emberizidae,[2] molecular phylogenetic studies have shown that Darwin's finches are members of the subfamily Coerebinae within the tanager family Thraupidae.

[7] A purported hybrid species (informally nicknamed "Big Bird") endemic to Daphne Major and formed almost four decades prior by hybridization between a vagrant Geospiza conirostris and a Geospiza fortis was also reported in 2017, though it has yet to be formally described.