The nonnative ambrosia beetles Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) are destructive pests of plants and trees growing in ornamental nurseries and tree fruit orchards. Perception of stress-induced volatiles plays an important role in aiding female X. germanus and X. crassiusculus in locating vulnerable hosts, while adult males of both species are flightless and not involved in host selection. Scanning electron microscopy was used to characterize the antennae of both species, which consisted of a scape, funicle, and club. Emphasis was placed on the type, structure, and distribution of sensilla associated with the antennal clubs of female and male X. germanus and X. crassiusculus. Sensilla observed on the anterior surface of the club for females and males of both species include one type of sensillum chaeticum (SC1), one type of sensillum trichodeum (ST1), and five types of sensilla basiconica (SB1–5). Sensilla are distributed in association with two sensory bands and/or a basal cluster. SB1, the most abundant sensilla type found on female and male clubs for both species, appears to be highly porous. No obvious sexual dimorphism was observed regarding sensilla type, but most types are more abundant on the antennal clubs of females compared with males for X. germanus and X. crassiusculus. Possible functions of the sensilla types are discussed based on morphology. These results provide an improved understanding of sensilla associated with X. germanus and X. crassiusculus that will aid electrophysiological investigations into their host selection behavior.