In trauma theory, research, and practice, post traumatic stress disorder (PTSD), a syndrome of psychobiological reactions to events perceived as cataclysmic or life threatening, often has been the focus of mental health interventions and research. Yet virtually missing from contemporary trauma literature is consideration of racism and ethnoviolence as catalysts for PTSD and related symptoms. The stress inducing effects of obviously life threatening racist or ethnoviolent events may be readily apparent to service providers and researchers although they have not been treated or investigated. However, observers seem not to view other types of racism and ethnoviolence as life-threatening (e.g., vicarious experiences, exposure to microaggressions) because the historical roots of the trauma are invisible. Such events may arouse immediate or delayed PTSD and related symptoms in the experiencing person if the event(s) serves as a catalyst for recalling previous personal memories or identity-group histories of threats to life or psychological integrity. Current PTSD assessment schedules are critiqued for their inappropriateness for assessing stress reactions to racism and ethnoviolence specifically; quantitative scales are criticized because of developers’ thoughtless application of traditional psychometric principles of scale development, such as maximizing the magnitude of internal consistency reliability coefficients. We recommend that researchers and practitioners conduct culturally responsive and racially informed assessment and interventions with African Americans, Latina/Latino Americans, Asian/Pacific Islander Americans, Native Americans, and related immigrant groups when they present with symptoms of trauma, particularly when their trauma responses are atypical or the precipitating stressor is ambiguous.