Aims: Decades of scientific research have found optimism to have wide-ranging effects on individuals' health and well-being. Researchers have largely examined optimism in adults, but have begun addressing the benefits of optimism in adolescents. Challenges and stressors in adolescence can threaten youths' subjective well-being; therefore, identifying factors that contribute to the growth of optimism could have important health implications. However, researchers have more often examined the effect of optimism on youth outcomes rather than factors that might positively or negatively contribute to the development of optimism., Methods: We assessed how salient developmental tasks (resilience, ethnic pride, and school attachment), family stress, and depressive problems individually contribute to Latinx youths' optimism at two time points (N = 123, 58.8% female, M age = 11.54 years)., Results: We found support for associations between both resilience and school attachment and optimism, but findings were weaker across time and with stressors included in the model. Depressive problems also appeared to weaken optimism across time., Conclusion: Given the established links between optimism and health, it will be important for researchers to continue to identify factors that contribute to the development of youth optimism, and assess whether they could be used in interventions to foster optimism., (© 2019 Wiley Periodicals, Inc.)