The present study attempts to replicate and extend Snyder et al. (2015, JPSP). The original study examined the latent factor structure of the EATQ-R, a commonly used measure of adolescent temperament, and then showed that the resulting latent factors (i.e., Effortful Control, Negative Emotionality, and Positive Emotionality) had theoretically meaningful concurrent associations with various measures of adolescent functioning (depression, anxiety, ADHD, relational aggression, and school performance and behavior). We performed these same analyses using data from a large sample of Mexican-origin youth (N=674), and also examined prospective associations between the three EATQ-R factors and measures of adolescent functioning assessed two years later. We found some evidence supporting the bifactor model fit reported in the original study but poor replication of the correlations among latent factors. Additionally, model comparisons demonstrated that correlated factors models led to more interpretable factors than the bifactor models. In contrast, we replicated most, but not all, of the concurrent correlations (and extended the findings to prospective associations) between the EATQ-R factors and measures of adolescent functioning, supporting the construct validity of the EATQ-R as a measure of adolescent temperament. Thus, these findings raise concerns about the generalizability of the factor structure identified by Snyder et al. (2015), but bolster claims about the generalizability of the concurrent and predictive validity of the EATQ-R. Overall, meaningful differences between the present findings and those of Snyder et al. highlight the importance of ongoing construct validation in youth temperament research, especially with participants from groups traditionally underrepresented in psychological research.