The current study evaluated the continuity between the diagnostic operationalizations of obsessive–compulsive personality disorder (OCPD) in the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition, both as traditionally operationalized and from the perspective of the alternative model of personality disorders. Using both self-report and informant measures, the study had the following four aims: (a) to examine the extent to which self-report and informant data correspond, (b) to investigate whether both self-report and informant measures of the alternative model of OCPD can predict traditional OCPD, (c) to determine if any traits additional to those proposed in the alternative model of OCPD can predict traditional OCPD, and (d) to investigate whether a measure of OCPD-specific impairment is better at predicting traditional OCPD than are measures of general impairment in personality functioning. A mental health sample of 214 participants was recruited and administered measures of both the traditional and alternative models of OCPD. Self-report data moderately corresponded with informant data, which is consistent with the literature. Results further confirmed rigid perfectionism as the core trait of OCPD. Perseveration and workaholism were also associated with OCPD. Hostility was identified as a trait deserving further research. A measure of OCPD-specific impairment demonstrated its ability to incrementally predict OCPD over general measures of impairment.