This report examines the importance and multidimensional nature of well-being, in general, and the well-being of Black, Native, Latinx, and Asian youth involved in systems of care, in particular. These young people must navigate three significant challenges: typical developmental issues and stressors associated with child and adolescent development; various difficulties associated with their experiences before and during their systems involvement; and experiences of racism and inequitable treatment in their daily living and in their involvement with different systems. For example, those who yield authority over Black, Native, Latinx, and Asian youth-- including educators, social workers, law enforcement, probation officers, prosecutors, and judges--may have explicit or implicit racial or ethnic biases that result in distorted perceptions and unjust treatment of these young people. Evidence underscores the need to strategically focus on fostering the well-being of youth served in systems of care--child welfare, courts, education, social services, juvenile justice, victim services, and health services systems--to increase the likelihood of more positive outcomes. A well-being frame is described that provides strategies to improve practice and policy that address the physical, social, emotional, intellectual, behavioral, and economic domains of well-being, as well as environmental and societal factors that contribute to youth's well-being. The well-being frame highlights the importance of employing diligent and consistent efforts at all levels of the social ecology--individual, interpersonal, community, and systemic--that will promote the equitable and just treatment of Black, Native, Latinx, and Asian youth across all systems of care. [This report is one in a series about improving outcomes for youth involved in systems of care. For three other reports in this series, see "Protective Factors for Youth Involved in Systems of Care" (ED617197); "Breaking the Stigma and Changing the Narrative: Strategies for Supporting Expectant and Parenting Youth Involved in Systems of Care" (ED617196); and "Shifting the Perceptions and Treatment of Black, Native, and Latinx Youth Involved in Systems of Care" (ED617199).]