Depersonalization (DEP) and derealization (DER) were examined among college students with and without borderline personality disorder (BPD) and/or dissociative disorders (DDs) by self-report and clinician assessment. The Steinberg Depersonalization Questionnaire (SDEPQ), the Steinberg Derealization Questionnaire (SDERQ), the Childhood Trauma Questionnaire, and the screening tool of the BPD section of the Structured Clinical Interview for DSM-IV (SCID-BPD) were administered to 1,301 students. Those with BPD (n=80) according to the SCID-BPD and 111 non-BPD controls were evaluated using the Structured Clinical Interview for DSM-IV Dissociative Disorders by a psychiatrist blind to the diagnosis. Of the participants, 19.7% reported SDEPQ (17.8%) and/or SDERQ (11.0%) scores above cutoff levels and impairment from these experiences. Principal component analysis of 26 items of both scales yielded 4 factors: cognitive-emotional self-detachment, perceptual detachment, bodily self-detachment, and detachment from reality. Participants with concurrent DD and BPD had the highest scores for DEP and DER in the clinical interview and self-report. The total number of BPD criteria was associated with the severity of childhood trauma and dissociation. Both BPD and DD were associated with clinician-assessed and self-reported DER, self-reported DEP, and the cognitive-emotional self-detachment factor. Unlike BPD, DD was associated with clinician-assessed DEP, and BPD was related to the self-reported detachment from reality factor. Although the latter was correlated with the total childhood trauma score, possibly because of dissociative amnesia, clinician-assessed DER was not. Being the closest factor to BPD, the factor of detachment from reality warrants further study.