Caenocoris nerii, common name oleander seedbug, is a species of ground bugs in the insect family Lygaeidae.

[1] The species name nerii refers to the main host plant Nerium oleander.

Two red markings appear on the shoulders of pronotum and at the inner margins of the hemielytra, which only partially cover the membranous blackish wings.

[6][7] Females usually lay eggs on the leaves of Nerium oleander (hence the common name of the species).

All stages of nymphs suck almost exclusively the milky juice of the main host plant (Nerium oleander), but they may also feed on Asclepiadaceae species.