Immigrant-origin adolescents represent the fastest growing segment of youth population in the United States, and in many urban schools they represent the majority of students. In this 3-wave longitudinal study, we explored trajectories of internalizing mental health symptoms (depression, anxiety, and somatic symptoms). The participants included 332 urban-residing first-and second-generation immigrant adolescents (44% male). Participants were recruited in 10th grade (M[subscript age] = 16.20 years, SD = 1.19), and 2 additional waves of data were gathered in 12-month intervals. Both generational and racial/ethnic background of the participants reflected the general demographics of urban centers in the United States. With individual growth curve modeling, the results show significant decline in internalizing mental health problems during the high school years. At the same time, greater exposure to acculturative stress predicted significantly more withdrawn, somatic, and anxious/depressed symptoms. Gender and generation status differences in internalizing mental health problems were also identified. (Contains 3 figures and 3 tables.)