In recent years, numerous states have significantly expanded access to pre-school, and policymakers at the federal level are considering legislation that would fund near-universal access across the country. However, while previous evaluations of pre-K programs have shown substantial long-term benefits for participants, the test score gains participants experience before kindergarten tend to fade out by third grade or sooner (i.e. Magnuson et al. 2007; Deming 2009; Puma et al. 2010). Authors have generated hypotheses about home-based factors that might drive the decline in test score effects, but little is understood about the school-based mechanisms that could moderate the persistence of pre-K effects. In this study, we pair student level data from a state-wide randomized controlled pre-K experiment with records of teacher observation scores from Tennessee’s new formal evaluation program to assess whether a student’s access to high quality early grade teachers moderates the persistence of pre-K effects. There are at least two ways teacher quality could alter persistence of pre-K effects. If high scoring teachers are better equipped to differentiate instruction and adjust to the higher levels of preparation of pre-K participants, we expect the benefits of pre-K to persist longer or even grow. Alternatively, if the better scoring teachers emphasize catching up the least prepared students, the gap between the pre-K participants and control students could close more rapidly. Our analyses indicate a small positive interaction between teacher quality and pre-K effect persistence on some but not all cognitive measures.