Racial microaggressions often occur in U.S. higher education. However, less is known about how White American students reason about their evaluations of racial microaggressions. The present study investigated how 213 White college students (54.46% cisgender women) attending a Primarily White Institution in the Southeast U.S. in the Fall of 2019 justified their evaluations of the acceptability of racial microaggressions presented in vignettes. Following Social Domain Theory, to assess participants' social reasoning, we conducted quantitative content analysis of participants' open-ended justifications for their evaluations. Multiple regression analyses revealed that participants were less likely to evaluate racial microaggressions as negative the more they employed justifications focused on (a) assuming that the behaviors in the situation followed conventions of the classroom, (b) judging the professor's response as correct, and (c) asserting that the behavior was likely to happen to anyone. Further, the higher participants' endorsement of color-blind attitudes the more likely they were to evaluate racial microaggressions as appropriate. However, reasoning centered on (a) assuming differential treatment based on race, (b) perceiving the behavior as harmful, and (c) considering the behavior was against conventional expectations was associated with finding racial microaggressions to be more negative. The present study highlights the value of investigating underlying reasoning behind evaluating racial microaggressions in addition to color-blind attitudes. The findings suggest that higher education professionals should consider interventions which pay particular attention to unpacking students' reasoning, untangling acceptance of Ethnocentric narratives and providing information that challenges classroom behaviors that, while potentially appearing conventional, in fact perpetuate harm through microaggressions.