The present study employed structured diagnostic interviews to assess the construct validity of the brief version of the Multidimensional Schizotypy Scale (MSS-B), which was developed to assess positive, negative, and disorganized dimensions of schizotypy. It was hypothesized that the MSS-B subscales would be associated with differential patterns of symptoms and impairment, comparable to findings for the full-length MSS. A total of 177 young adults completed structured diagnostic interviews assessing symptoms and impairment. As hypothesized, MSS-B positive schizotypy was significantly associated with interview ratings of positive (psychotic-like) symptoms, as well as schizotypal and paranoid personality disorder traits. MSS-B negative schizotypy was associated with interview ratings of negative symptoms, as well as schizoid, paranoid, and schizotypal traits. Furthermore, negative schizotypy predicted Cluster A personality disorder diagnoses. MSS-B disorganized schizotypy was associated with interview ratings of disorganized symptoms. All three schizotypy dimensions were associated with impaired functioning. This was the first study to evaluate the validity of the MSS-B using interview measures, and the pattern of findings for each MSS-B subscale was closely comparable to the findings for the full-length MSS. Contrary to our hypothesis, cannabis use was largely unassociated with psychotic-like symptoms and did not moderate the expression of the schizotypy dimensions. The MSS-B has good psychometric properties, high concordance with the full-length MSS, and good construct validity. Thus, it appears to be a promising brief alternative to traditional schizotypy measures.