This qualitative study examined instances of racial identity invalidation among 49 Black/White Biracial individuals. Transcriptions of participants discussing their most stressful experience of invalidation were coded for themes using content analysis. Themes that emerged provided a rich description of Biracial participants’ perceptions of why invalidation occurs and why perpetrators invalidated the individual. Also addressed are Biracial people’s thoughts, feelings, and reactions in response to the invalidation, and the effect of the invalidating experience on racial identity. Implications for research and preventive interventions are provided.