The Multidimensional Pain Inventory (MPI) is one of the most widely used instruments to assess patients' coping with chronic pain. It provides a psychosocial classification system that categorizes patients into three coping styles: Adaptive, Dysfunctional, and Interpersonally Distressed. To date, comprehensive information about the validity of the MPI taxonomy obtained from informants other than the patient has been unavailable. This has limited conclusions about the extent to which the MPI captures patients' adaptation to chronic pain beyond self-report. The present study is the first to examine whether the distinct multidimensional profiles underlying the patient clusters can be confirmed by proxy report. Ninety-nine chronic pain patients, their partners, and their healthcare providers participated in the study. Patients completed the MPI twice to determine stability of classification. Partners and providers rated the patient on MPI proxy versions developed for this study. Results revealed that partner- and provider-reported MPI ratings corresponded with the self-report patient profiles. The profiles of patients showing classification stability rather than switching of cluster assignment between the two MPI assessments had the highest correspondence with proxy ratings. These results extend prior validity research on the MPI and demonstrate that differential psychological adaptational styles to chronic pain can be reliably recognized by partners and healthcare providers.