Multiculturalism and interethnic relations remain central themes in psychological research within Malaysia's richly diverse society—comprising Malays, Chinese, Indians, and indigenous groups. While traditional theories, such as Social Identity Theory, have offered foundational insights into group dynamics, contemporary approaches now emphasize more integrative and context-sensitive models. Notably, the Multicultural Identity Integration (MII) framework has gained traction, highlighting how individuals navigate multiple cultural identities and the psychological outcomes of perceived harmony or conflict between these identities. In Malaysia, where ethnicity is closely tied to religion, language, and political representation, the MII offers a nuanced lens for understanding interethnic relations, particularly among youth and urban populations. Complementing this is the interculturalism model, which promotes active interaction and mutual adaptation between groups, rather than passive coexistence. This approach aligns with national unity efforts such as "Malaysia MADANI," which encourages shared values and respect among citizens. Additionally, the role of cultural competence among mental health professionals is gaining prominence, emphasizing the need for culturally responsive interventions that acknowledge and respect clients' cultural backgrounds. In practice, Malaysian psychologists are increasingly called to develop frameworks that integrate multicultural sensitivity into counselling, psychotherapy, and community mental health programs. This initiative includes addressing issues such as cultural stigma surrounding mental illness, language barriers, and differing cultural interpretations of psychological distress. Governmental policies and national unity campaigns also play a crucial role in shaping public attitudes and interethnic engagement. Despite significant progress, gaps remain in the representation of minority voices and the accessibility of mental health services across ethnic lines. Future research must prioritize longitudinal and intersectional studies that capture the evolving nature of interethnic dynamics in Malaysia's rapidly changing sociopolitical landscape. A robust multicultural approach in psychological research and practice is essential for fostering inclusive mental health services and strengthening social harmony in Malaysia's diverse society.