Models of basic personality structure are among the most widely used frameworks in psychology and beyond, and they have considerably advanced the understanding of individual differences in a plethora of consequential outcomes. Over the past decades, two such models have become most widely used: the Five Factor Model (FFM) or Big Five, respectively, and the HEXACO Model of Personality. However, there is no large-scale empirical evidence on the general comparability of these models. Here, we provide the first comprehensive meta-analysis on (a) the correspondence of the FFM/Big Five and HEXACO dimensions, (b) the scope of trait content the models cover, and (c) the orthogonality (i.e., degree of independence) of dimensions within the models. Results based on 152 (published and unpublished) samples and 6,828 unique effects showed that the HEXACO dimensions incorporate notable conceptual differences compared to the FFM/Big Five dimensions, resulting in a broader coverage of the personality space and less redundancy between dimensions. Moreover, moderator analyses revealed substantial differences between operationalizations of the FFM/Big Five. Taken together, these findings have important theoretical and practical implications for the understanding of basic personality dimensions and their assessment.