In 2020, youth experienced transformative change, as schools shut down and adolescents’ social and school lives moved fully online due to the COVID-19 pandemic. Amid this upheaval, adolescents also experienced the normative changes of the pubertal transition, a well-known time of rapid physical and psychosocial change that coincides with increases in depressive symptoms for youth. The present analysis draws on a sample of N = 596 female youth recruited continuously from 2014 to 2023 to explore how an altered social landscape may change the experience of puberty. Multiple linear regression was utilized to examine cohort differences in the associations between pubertal status and timing with depressive symptoms, as well as associations between months since menarche and age at menarche with depressive symptoms. We found that previously established associations between pubertal status and timing with depressive symptoms were not replicated in the pandemic cohort; however, months since menarche was significantly associated with depressive symptoms in both pre- and pandemic cohorts. Our findings stress the importance of considering broader socio-historical context in studying adolescent development. They also highlight the value of considering the continuous reproductive development that occurs after menarche and extends the critical period for the development of internalizing symptoms in adolescence. In the spring of 2020, the spread of the novel coronavirus led to a global pandemic and the shutdown of schools across the United States, which altered the psychosocial landscapes of youth. As families navigated school closures, financial uncertainty and health stressors, youth also adjusted to remote schooling and changing patterns of social interaction. During this time, greater youth self and parent reports of stress and depressive symptoms were observed in response to the transformative effects of the pandemic (Racine et al., JAMA Pediatrics 175:1142–1150, 2021; Hawes et al., Psychological Medicine 52:3222–3230, 2022). However, many aspects of adolescence continued forward—albeit in an altered and less predictable environment. Chief among these was puberty – or the rapid physical and psychosocial changes that mark the transition from childhood into adolescence. Pubertal development has consistently served as a critical juncture for mental health, robustly associated with increases in depressive symptoms and rates of depression. Given the transformative effects of the pandemic on youth’s social landscapes and mood and well-being, understanding how established links between mental health and puberty may have evolved during the pandemic is a critical task for researchers. The present study examines these relationships in two samples of adolescent girls, collected before and after the onset of the COVID-19 pandemic that began in 2020.