The Sage Handbook of Psychological Perspectives on Diversity, Equity, and Inclusion is a landmark volume that brings together global scholarship to examine the psychological foundations, challenges, and possibilities of DEI in today’s world. At a time when DEI efforts are increasingly under political and cultural scrutiny, this handbook offers a timely, evidence-based, and interdisciplinary resource for understanding and advancing equity and inclusion across societies. Spanning 46 chapters and contributions from authors in 16 countries, the handbook explores the psychological dimensions of DEI while drawing on insights from sociology, political science, and related fields. It critically reviews the state of the literature, identifies promising directions for future research, and offers practical guidance for policy and practice. The volume is structured into seven thematic sections, covering foundational theories, dynamic processes, strategies for change, group-specific experiences, sectoral applications, and future directions. With a commitment to intellectual rigor and respectful dialogue, the Handbook embraces the creative tensions that exist within DEI work. This handbook does not shy away from critique—it invites it, offering a space for reflection, disagreement, and growth. It is both a scholarly resource and a call to action for building more just, inclusive, and equitable societies. Section 1: Introduction to DEI Section 2: Foundations for Understanding and Promoting DEI Section 3: Dynamic Processes for Understanding and Promoting DEI Section 4: Strategies for Promoting DEI Section 5: Understanding and Promoting DEI for Specific Groups Section 6: Understanding and Promoting DEI in Specific Sectors and Contexts Section 7: Where Next for DEI?