As a primary system in which the child develops, the impact of family cannot be understated. Each member’s emotional and behavioral health, relationships to one another, and the overall family environment interact to shape the child’s experiences, perceptions, and expressions. Family involvement is key to comprehensive mental health assessment, providing valuable insights into the child and family system that lead to a more holistic understanding of a case and relevant recommendations. This chapter focuses on families in their many diverse constellations and ways to engage them in the assessment process. We discuss the many roles that families play, as both sources of information and as change agents. Then, the chapter turns to conducting a culturally responsive family interview, as we provide practical advice on who to include, what to cover, and how to navigate the interview. Moving beyond interacting with a single individual to work with a complex family system amplifies potential difficulties alongside opportunities, and so we discuss common trepidations and ways of interacting more effectively with families. We apply these principles, strategies, and techniques to diverse family systems through case illustrations. The chapter closes with a specific approach for working at the family level.