Mental health disparities among first-generation immigrants to the United States are intricately linked to the historical and sociopolitical context of immigration. The Immigration and Nationality Act of 1965 and policies such as Deferred Action for Childhood Arrivals (DACA) have shaped the demographic and experiential landscape of first-generation immigrants, influencing their mental health outcomes. Objective: This study aims to examine the mental health disparities experienced by first-generation immigrants in the United States, identifying the contributing factors and exploring effective strategies for addressing these disparities. Methods: A comprehensive literature review was conducted, analyzing studies on mental health outcomes among first-generation immigrants. The review focused on factors contributing to mental health disparities, including pre-migration experiences, migration-related stressors, post-migration challenges, and systemic barriers to mental health care access. The review also explored intersectionality and its impact on mental health, as well as case studies and examples of successful interventions. Results: The "immigrant paradox" suggests that immigrants often exhibit better mental health outcomes than native-born individuals, though this effect diminishes over time. Factors such as strong family ties and community support initially contribute to this mental health advantage. However, post-migration challenges, including acculturation stress, socioeconomic hardship, and discrimination, often lead to a decline in mental health. Certain mental health conditions, such as PTSD and anxiety disorders, are more prevalent among specific immigrant groups, particularly those fleeing conflict or persecution. Structural, cultural, and systemic barriers hinder access to mental health care, exacerbating disparities. Successful interventions often involve community-based approaches, culturally competent care, and integrated service models. Conclusion: Addressing mental health disparities among first-generation immigrants requires a multifaceted approach, including community engagement, policy interventions, and culturally competent care. By investing in research and implementing evidence-based interventions, it is possible to reduce mental health disparities and improve outcomes for first-generation immigrants. Future research should focus on long-term mental health trajectories, the impact of digital technologies, and the role of social networks.