This chapter introduces the financial domain as a critical component of behavioral health, complementing traditional domains that include mental, physical, coping, and social health. Financial health is defined as a person’s capacity to wield material means in support of their overall well-being, emerging from three interconnected components: financial precarity, financial efficacy, and financial well-being. Financial precarity encompasses both objective financial conditions (e.g., income volatility, debt burden, emergency savings) and subjective experiences (e.g., financial anxiety, stress, hopelessness). Financial efficacy represents one’s ability and confidence to manage financial challenges through problem-solving, goal attainment, and emotional regulation. Financial well-being reflects stress in managing finances in the present and expectations of financial stability in the future, enabling value-aligned financial choices. These components interact bidirectionally with other behavioral health domains, creating complex relationships where financial concerns can both influence and be influenced by mental health, physical health, coping mechanisms, and social relationships. Understanding these interconnections is essential for helping professionals across disciplines to recognize how financial circumstances affect overall well-being and to develop more effective, holistic interventions that address the full spectrum of human health and functioning.