The present study addressed gaps in puberty and weathering research by examining the relation between peer racial discrimination, pubertal timing, internalizing and externalizing symptoms, and neighborhood context among a longitudinal sample of U.S. Mexican boys. Using three waves of data (N = 383; mean ages: 10.3-15.8 years), we examined the weathering hypothesis: Whether peer racial discrimination experiences in late childhood predicted earlier pubertal timing in adolescence and subsequent mental health problems. We also examined whether variability in youths' neighborhood contexts qualified these associations. Consistent with the weathering hypothesis, exposure to peer racial discrimination in 5th grade, predicated earlier pubertal timing in the 7th grade, which, in turn, predicted increases in internalizing symptoms in the 10th grade. However, this pattern only applied to boys residing in neighborhoods with higher levels of Latinx concentration in 5th grade. Additionally, early timing in the 7th grade predicted increases in externalizing symptoms, but this association was significant only when boys lived in neighborhoods that were lower on Latinx concentration. There was evidence of weathering in context with specific implications for internalizing symptoms, and that neighborhood Latinx concentration was both inhibiting and promoting at unique places in the hypothesized model. The findings advance existing understandings of weathering patterns and individual variation in pubertal timing among U.S. Mexican boys. (PsycInfo Database Record (c) 2022 APA, all rights reserved).