This chapter serves as the foundation for exploration of the definition, history, framework, nature, and significance of interdisciplinary practice in counseling and human services to improve outcomes for clients. It discusses the concept of “interdisciplinary” and “disciplinary foundations” to construct interdisciplinary linkages. The chapter explores common core characteristics of human services practice across the disciplines of counseling, rehabilitation counseling, social work, psychology, and allied health. It presents the information (a) roles and functions, (b) values and ideas, (c) cultural competence, and (d) knowledge, skills, and competence in the shared areas of human growth and development, clinical assessment and evaluation, goals development and implementation, application of interventions and evidence-based practices, and ethics. It also identifies the strategies for establishing interdisciplinary collaboration across various human services, health, and behavioral disciplines. Finally, the chapter examines the challenges and benefits of interdisciplinary practice within human services practice.