Integrating clinical psychology, community psychology, and cultural psychology into mental health assessment with youth and their families holds great promise. This chapter reviews foundational challenges embedded in and posed by mental health fields and care systems, past and present. It explores how these fields have grown and developed, expanding beyond a biopsycho/biomedical, individual-focused approach to striving toward incorporating sociocultural, systems-focused frames to understand mental health over the past 100 years. In the book, we explored how practitioners can follow four principles to integrate clinical, community, and cultural psychology into mental health assessment: (1) Consistently collaborate and communicate with all stakeholders; (2) remember your purpose—and still respond flexibly; (3) keep an open mind but not an empty head; and (4) consider culture and context in all conclusions. In this chapter, we summarize our approach to assessment by illustrating how these principles undergird every aspect of the evaluation process. We argue that by following this principles-based approach, clinicians can improve mental health assessments, in turn improving mental health care and, ultimately, mental health. The chapter ends with key questions for the field to consider as it develops, alongside a call to action.