Technical Abstract: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and adults transmit phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease (huanglongbing). Host plant resistance ultimately may provide the most effective, economical, environmentally safe, and sustainable method of control, but host plant resistance in citrus and relatives to ACP has not been conclusively demonstrated to date. Very low abundances of all life stages of ACP were found on two genotypes of Poncirus trifoliata L. in a field survey, so in this study we tested whether 81 genotypes of P. trifoliata and xCitroncirus sp. (hybrids of P. trifoliata and another parent species) were resistant to ACP by determining whether these genotypes influence oviposition and lifespan of adults in no-choice tests. There was a higher abundance of eggs on the control (Citrus macrophylla Wester) than on all genotypes of P. trifoliata, except for the genotype ‘Towne ‘G”, and on 15 of 34 genotypes of xCitroncirus sp. Lifespan of adults also was ~2-5 times longer on C. macrophylla than on P. trifoliata ‘Flying Dragon B’ and most of the trifoliate hybrids that also were resistant to oviposition. Our work is the first to conclusively identify resistance to ACP in citrus germplasm, but we must next identify the genotypic and phenotypic traits that promote resistance in order to create commercial varieties of citrus that reduce the population of ACP and lower the incidence of citrus greening disease.