Prior research on inclusiveness has largely centered on external influences such as diversity policies, leadership directives, and cultural norms. In contrast, we propose that inner authenticity—feeling true to oneself—can also shape one’s openness and inclusiveness toward others. Across five main and eight supplementary studies (five preregistered; total N > 3,000) conducted in both China and the U.S., we show that state authenticity fosters inclusiveness both attitudinally and behaviorally. Our experiments examine individual responses to varying social domains, including non‑traditional life choices (e.g., staying unmarried or child‑free), feminist attire, unconventional hobbies, quiet quitting, immigration, and the controversial “lying flat” (躺平) phenomenon. We show that this effect is explained by perspective-taking, above and beyond the influence of positive affect and self-enhancement motives. Moreover, we rule out inauthenticity as an alternative explanation. Together, these findings establish authenticity as a self-directed, self-transcendent pathway to inclusiveness, advancing theoretical accounts of self-processes in intergroup relations.