This chapter examines the health challenges faced by migrant adolescents, focusing both on international trends and the specific contexts of Chile and El Salvador, two Latin American countries with opposite immigration patterns amid increasing global migration. Despite their active participation in migration, adolescent migrants are often underrepresented in research, leaving their unique developmental needs insufficiently addressed. Through a comprehensive literature review focused on critical health areas—mental health, sexual and reproductive health, substance use, youth violence, and the impact of the COVID-19 pandemic—this work reveals how migration and health intersect uniquely in these two nations. The chapter also highlights strategies to improve health outcomes, emphasizing the need for enhanced training of healthcare professionals to address the specific experiences and disparities encountered by migrant adolescents. By integrating international and national studies, this work seeks to fill a critical gap in migration and health literature, offering insights relevant to other contexts, particularly within the Global South.