Youth involved in the juvenile justice system (YIJ), including those under community supervision, have disproportionately high rates of behavioral health disorders compared to community samples, yet the vast majority do not receive the care they need. When left unaddressed, youths' behavioral health concerns can contribute to deepening juvenile justice involvement, which is frequently accompanied by increasing severity of behavioral health disorders and negative long-term ramifications for youth, families, and communities. The majority of YIJ are under community supervision, meaning they reside in the community and must receive behavioral health treatment through the community-based behavioral health system. To highlight the need for innovative approaches that break this cycle by closing the gap between clinical need and uptake of effective treatment for these high-risk and often overlooked youth, we synthesize existing literature on the prevalence of psychiatric disorders and intersecting domains of risk for disorder and justice involvement among youth under community supervision, drawing on ecodevelopmental and ecological systems theory to advance an understanding of specific barriers to services for youth under community supervision. We review existing efforts to facilitate treatment access and conclude with data-driven recommendations for future research, clinical practice, and policy changes.