Wyeomyia (Wyeomyia) mitchellii (Theobald) (Diptera: Culicidae) was recovered for the first time on Guam, United States of America, in 2017. Larval specimens were collected from water-filled axils of bromeliads during a larval survey carried out in a residential neighborhood of the Chalan Pago/Ordot area. Native to the New World, Wy. mitchellii has likely made its way to the Pacific Islands through the possibly illegal import of ornamental bromeliads. While this mosquito does not represent a significant threat to public health, this finding highlights the vulnerability of the Pacific Islands to the introduction of exotic species, including mosquito species that may increase public health risks.