The response of Western flower thrips, Frankliniella occidentalis (Pergande) to several species of Lycopersicon was evaluated. In thumbtack bioassays for antixenosis, L. Hirsutum Muller, L. hirsutum f glabratum Humb. & Bonpl., and L. pennellii Corr. were all highly antixenic to thrips nymphs, and L. chilense Dun. was moderately antixenic. Thrips nymphs readily moved onto leaves of L. peruvianwn (L.) Miller, L. parviflorum Rick, L. esculentumMiller ‘Anahu’ and ‘Hey de los Tempranos’, and L. chmielewskii Rick, indicating that these plant accessions lacked antixenosis to the western flower thrips. Feeding damage by adult western flower thrips varied significantly among leaves of Lycopersicon species. The greatest amount of feeding occurred on L. peruvianum and L. parvifiorum. The least amount of feeding occurred on L. hirsutum. Adult western flower thrips feeding on accessions that had strong antixenosis caused shriveled and distorted epidermal cells with no apparent damage to internal mesophyll cells. Among those accessions that lacked antixenosis, adult thrips feeding resulted in severely damaged epidermal, palisade, and spongy parenchyma cells. In these accessions many mesophyll cells were destroyed and cell contents scattered in the intercellular space between spongy parenchyma cells. Adult western flower thrips fed on flowers of all the Lycopersicon species evaluated without significant differences in feeding damage among plant accessions. The importance of these findings to breeding programs for resistance to the thrips transmitted virus, tomato spotted wilt tospovirus, is discussed.