Despite the vital role that trailing partners play for successful expatriation, we still know very little about what actually causes partners to thrive and integrate effectively into the new cultural context. However, as indications have emerged that the personality of partners could be key to a favorable acculturation trajectory, we set out to explore this further. More specifically, we assess the role of expatriate partners’ dispositional affectivity, that is, positive and negative affectivity. We examine this in relation to internal acculturation (in the form of interaction and general adjustment) and external acculturation (in the form of local community embeddedness and intentions to stay or to return home). Drawing on the data of 123 trailing partners, full support was found for three out of four hypotheses regarding the effects of positive affectivity. Further, a marginally significant negative association was identified for the relationship between positive affectivity and repatriation intentions. For negative affectivity, two hypotheses were met. Interestingly, no significant influence of negative affectivity on community embeddedness was found. The association between negative affectivity and interaction adjustment was marginally significant indicating some tentative support. In sum, this study corroborates that dispositional affectivity is an overall important concept to explain trailing partners’ acculturation. However, the role of positive and negative affectivity seems to vary along the different proxies of internal and external acculturation.