Publicly funded pre-K is often touted as a means to narrow achievement gaps, but this goal is less likely to be achieved if poor/minority children do not, at a minimum, attend equal quality pre-K as their non-poor/non-minority peers. In this paper I find large "quality gaps" in public pre-K between poor/minority students and non-poor/non-minority students, ranging from 0.3 to 0.7 SD on a range of classroom observational measures. I also find that even after adjusting for several classroom characteristics, significant and sizable quality gaps remain. Finally, I find much between-state variation in gap magnitudes, and that state-level quality gaps are related to state-level residential segregation. These findings are particularly troubling if a goal of public pre-K is to minimize inequality. (author abstract)