Community-based therapists are frequently faced with the complex task of applying existing research knowledge to clients who may differ markedly from those enrolled in controlled outcome studies. The current paper examines the utility of modular psychotherapy design as one method of facilitating the flexible delivery of evidence-based mental health services to ethnically and culturally diverse children and families. Modularity complements existing approaches to the provision of culturally-sensitive, empirically-informed treatment through its ability to balance the prioritization of research evidence and local practitioner cultural knowledge. Specific applications of modular principles to clinical work with diverse youth are highlighted. Special considerations and limitations relevant to modular psychotherapy and the overall mental health services research literature are discussed, as well as the continued importance of individual clinicians' cultural competence and use of treatment progress monitoring, both of which should be combined with identified treatment modules to support the delivery of high-quality care.