This study examines a diverse set of nearly 100 private institutions that adopted test-optional undergraduate admissions policies between 2005-2006 and 2015-2016. Using comparative interrupted time series analysis and difference-in-differences with matching, I find that test-optional policies were associated with a 3% to 4% increase in Pell Grant recipients, a 10% to 12% increase in first-time students from underrepresented racial/ethnic backgrounds, and a 6% to 8% increase in first-time enrollment of women. Overall, I do not detect clear evidence of changes in application volume or yield rate. Subgroup analyses suggest that these patterns were generally similar for both the more selective and the less selective institutions examined. These findings provide evidence regarding the potential--and the limitations--of using test-optional policies to improve equity in admissions.