Educational inequities between White Americans and Black and Latinx Americans have grown in recent decades. However, the present research documents that many members of the public may be misinformed about this reality. Three initial studies, with 813 undergraduates and online participants, demonstrate that many individuals overestimate the progress made towards reaching White-Black and White-Latinx equality in degree attainment over time, incorrectly believing that Black and Latinx Americans' degree attainment rates increased by more than twice as much as they actually had from 1980 to 2015. This work also documents potential consequences of these misperceptions: two follow-up experiments, with 621 undergraduates and online participants, find that correcting these misperceptions reduced attributions of these disparities to a lack of effort among Black students and increased support for equity-enhancing policies, especially among those most prone to these misperceptions. However, these corrective effects weakened over time. Together, these results suggest that unfounded optimism regarding progress towards racial equity in education may pose a major barrier to actual progress in this domain.