When people talk about social categories such as “men and women” or “the rich and poor,” what factors determine which group will be mentioned first, and what does this order communicate to the audience? Scholars have suggested that a group is more likely to be mentioned first if it has more power or if it is more closely linked to the speaker. We argue that these principles do not adequately capture how people order social categories and are rather instantiations of a broader explanatory principle—communicational relevance. Communicational relevance is defined as the quality of being central to the communicational goals of the interlocutor. We have tested this idea with archival and experimental data. Our results suggest that communicational relevance does a better job of predicting word order choices than the factors proposed so far and can explain why people sometimes put less powerful or more distant parties first. We also show that the order of social categories has communicational consequences because people assign more relevance to a social category if it is mentioned first rather than second. We discuss the implications of these findings for the maintenance and transmission of stereotypes.