What is the relationship between people’s trust in specified outgroups (such as ‘French people’ or ‘immigrants’) and their generalised trust? This relationship has never been empirically tested, which is troubling for the large body of research on the link between ethnic diversity and trust which seemingly assumes that outgroup trust does affect generalised trust. In this paper, I use individual-level survey data to examine how outgroup trust affects generalised trust in the United States and Croatia. Although the two types of trust are correlated, I find no evidence that people account for outgroup salience when translating outgroup trust into generalised trust, as previous theories have suggested. This raises the possibility that a different type of mechanism may be responsible instead, or perhaps that the association is non-causal and trust is a fixed personality trait which is not alterable by experience. In either case, it seems that the conventional explanation for how ethnic diversity reduces generalised trust—namely that it reduces outgroup trust which then feeds through into lower generalised trust—may need to be revised. I conclude by discussing limitations and some suggestions for further research.