The aim of this study was to test an integrative model of intercultural social self-efficacy using a sample of 124 Vietnamese migrant university students in Australia. According to the model, Asians' intercultural social self-efficacy in western societies would be predicted by three of the five Big Five personality factors (higher levels of extraversion and openness, and a lower level of neuroticism), three cultural relocation variables (a weaker ethnic identification, a higher level of fluency in the host language, and a longer period of residence in the host country), and their co-ethnic social self-efficacy. As well, the model tested if co-ethnic social self-efficacy would mediate the effects of the personality variables on intercultural social self-efficacy. Subsequent path analysis results partially supported the model tested. There were significant total effects of co-ethnic social self-efficacy, weak Vietnamese ethnic identification, English fluency, extraversion, and openness on intercultural social self-efficacy. The effect of extraversion was mediated by co-ethnic social self-efficacy. The results highlight the relevance of not only cultural relocation factors, but also the possession of relatively stable personal resources (in the form of characteristic social efficacy, extraversion, and openness), to acculturating Asians' social efficacy in interacting with host nationals. Methodological limitations of the present study and implications of the findings for both the sociocultural adjustment literature and training for migrant students are discussed.