The COVID-19 pandemic disrupted school, work, and daily life on a global scale. In the wake of this unprecedented health crisis, schools across the United States were forced to abruptly adapt their educational delivery models. Understanding how student learning trajectories shifted throughout the ongoing pandemic is critical for equipping educators, policy makers, families, and other vested partners to respond to and serve students going forward. Using a national sample of oral reading fluency (ORF) scores, we estimated trajectories of literacy development for students in grades 1-5 before and during the pandemic. Results showed that students began fall 2020 (after pandemic onset) with lower average ORF scores than their same-grade peers from the prior (i.e., prepandemic) year. In addition, this disparity in reading fluency between cohorts widened between the beginning- and middle-of-year benchmark periods. Schools must be prepared to serve a population of students unlike that of before the pandemic onset.