Immigration—both the experience of migrating and events after migration—can affect the mental health and well-being of immigrants and their communities. However, evidence suggests that immigrants in the United States do not access mental health services to the same extent as nonimmigrants. In particular, immigrant adolescents and young adults may have unique stressors related to their developmental stage, experiences in school and with peer groups, and shifting roles within family systems. This scoping review summarizes findings from published research studies and practitioner-focused gray literature about the mental health needs of immigrant communities in the United States. The review finds that specific mental health needs vary across factors like age, racial/ethnic group, immigration status, and place of residency. Findings also indicate that structural factors like immigration-related laws affect both access to mental health services and stressors in the overall environment for immigrants and their families. This review also explores models of community-level initiatives that utilize strengths-based approaches to promoting mental health and well-being among immigrant communities. Findings highlight the need for a better understanding of the mental health needs and current barriers to care among diverse immigrant populations, as immigration continues to play a major role in U.S. public policy and discourse. The COVID-19 pandemic taking place as this article goes to press in 2020 also raises questions regarding health equity and access for marginalized populations, including immigrants and their communities, and so these findings also indicate the need for further interdisciplinary research to assess intersections among the pandemic’s many impacts, including those related to mental health and well-being.