The initial version of the Multicultural Guidelines, titled Guidelines on Multicultural Education, Training, Research, Practice, and Organizational Change for Psychologists, was published in 2002. Since then, there has been significant growth in research and theory regarding multicultural contexts. The revised Multicultural Guidelines are conceptualized to reconsider diversity and multicultural practice within professional psychology at this period in time, with intersectionality as its primary purview. Psychologists are encouraged to incorporate developmental and contextual antecedents of identity and consider how they can be acknowledged, addressed, and embraced to generate more effective models of professional engagement. The Multicultural Guidelines incorporate broad reference group identities that acknowledge within-group differences and the role of self-definition. Identity is shaped across contexts and time by cultural influences including age, generation, gender, gender identity, ethnicity, race, religion, spirituality, language, sexual orientation, social class, education, employment, ability status, national origin, immigration status, and historical as well as ongoing experiences of marginalization. The theoretical model, a layered ecological model of the Multicultural Guidelines, is presented along with 10 corresponding guidelines. The guidelines are applicable to psychologists in their work with clients, students, research participants, and in practice, education, research, and/or consultation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).