The present study tested the developmental links between maternal closeness and support and measures of depression and anxiety symptoms, and whether these links were conditioned by pubertal status. It was hypothesized that pubertal status (early) would potentiate the negative links (stronger relationships) between maternal positive parenting and developmental changes in internalizing problems in comparison to youth who mature on time or late. Four waves of self-report data were collected from 340 Czech female adolescents (Mage = 12.34 years, SD = 0.87 at W1), from 6th and 7th grades, including BMI, pubertal development, maternal closeness and support, as well as depressive and anxiety symptoms. Analyses included one-way ANOVAs by grade cohort, BMI, and pubertal status, as well as cross-lagged panel model tests, with follow-up multi-group tests. Results provided evidence of bidirectional effects between closeness and support with developmental changes in depressive symptoms, and some evidence of the same in anxiety symptoms. Multi-group tests provided no evidence of moderation effects by grade cohort, BMI groups, or pubertal status. Findings provide important evidence of how positive parenting predicted developmental changes in internalizing problems, only six months apart; they also provided important evidence that neither BMI nor pubertal status moderated the parenting-internalizing problems links.