Theory of Mind (ToM)—the ability to infer others’ mental states—is fundamental to social cognition. Social categorization, the grouping of individuals into in-group or out-group categories, shapes these inferences. These processes co-occur during facial perception, with recent research suggesting both shared neurocognitive mechanisms and modulation of ToM by social category cues. However, existing tools for studying the impact of racial diversity on social cognition are limited: some databases prioritize racial representation but restrict stimuli to the six basic emotions, while others broaden mental state diversity but lack diversity in social appearance.Here we introduce the McGill Diverse Face Database, a validated set of 1,286 images of 14 actors from socially perceived racial categories portraying 92 complex mental states. Validation included three experiments: (1) a four-alternative forced-choice task assessing recognition accuracy, (2) a “point-and-click” task rating valence and arousal in a two-dimensional affective space, and (3) a trait-rating task evaluating perceived actor characteristics. Participants accurately identified mental states across categories (77 % of stimuli). Mean valence–arousal ratings revealed a non-linear one-dimensional manifold structure that correlated with behavioral measures. An interactive online visualization allows users to explore this “Theory of Mind manifold” (https://hctor99.github.io/TheoryofMindManifold/). By integrating social-category diversity with complex emotional expression, this database provides a new resource for studying how socially perceived group membership shapes the perception and inference of mental states.