Achagua is a small Neotropical genus of moths in the family Geometridae, with species found in South and Central America.

[1] Achagua was erected by Frederick H. Rindge in 1983, and placed in tribe Nacophorini of the Geometridae.

[2][3] Phylogenetic research in 2019 confirmed its placement in Nacophorini, and placed Achagua as sister taxon to the genera Gabriola and Cargolia.

[1] At the time of the Rindge's description, Achagua obsoleta was the sole formally described species in the genus, although Rindge mentioned—but did not provide a formal first description or name of—a second species.

This Nacophorini-related article is a stub.