School bullying receives considerable attention in research and in prevention and intervention activities, but microaggressions (a related form of aggressive behaviors) are largely ignored. This exploratory and descriptive qualitative study reports on diverse students' experiences with microaggressions related to racism, homophobia, transphobia, and anti-fat bias, and school responses to such incidents. As part of a larger study on bullying, we conducted four focus groups (n = 25 youth) and 13 dyadic interviews (n = 26 youth and parents). Questions about experiences of bullying gave rise to descriptions of numerous incidents that were classified as microaggressions in inductive thematic analysis. Four themes emerged: (1) Many types of microaggressions communicate marginalization, stereotypes, and lack of acceptance; (2) Experiences of microaggressions negatively affect mental health and school engagement; (3) Many youth stay silent in the face of microaggressions, but some stand up to aggressors; and (4) School and teacher responses to microaggressions are perceived mostly as nonexistent or ineffective. Schools should consider microaggressions a subset of bullying behaviors and address them in prevention activities, as well as provide resources and activities to engender a school climate that is respectful and supportive of diverse students.