Adolescent hope can promote the emotional and behavioral well-being of Latinx families. Positive family functioning may foster adolescent hope, whereas cultural stress may compromise adolescent hope and well-being. We examined how adolescent hope changed over time, and whether cultural stress and family functioning predicted emotional and behavioral health via adolescent hope intercept and slope. Recent Latinx immigrant adolescents (M[subscript age] = 14.51) and parents (M[subscript age] = 41.09; N = 302; n = 150 from Los Angeles; n = 152 from Miami) completed measures of above constructs over 3 years (Summer 2010 to Spring 2013). Latent growth curve modeling indicated that adolescent hope increased over time. Higher cultural stress predicted lower initial hope. Higher family functioning predicted higher initial levels of and less steep increase in hope. Increase in hope predicted better emotional and behavioral health. Family functioning predicted better health outcomes by way of hope.