Parental sense of competence is one of the central dimensions targeted on psychosocial interventions aimed at supporting at-risk families. Researchers and practitioners need reliable instruments to assess the parental role adapted for these families. Although the parental sense of competence (PSOC) scale has been frequently used to assess this construct, there is still no adapted version for Portuguese parents. In this study, the reliability, validity and factor structure of the PSOC scale is examined with a clinical sample of 146 mothers from at-risk families receiving psychosocial interventions for family preservation from Child Protective Services. Results show that the Portuguese version of the PSOC measures three distinct constructs with acceptable psychometric properties: efficacy, dissatisfaction and controllability. As expected, the obtained factors were significantly and positively related to parenting alliance and family cohesion, and negatively associated with parenting stress. In sum, the proposed Portuguese version shows reliability and validity evidences to measure three relevant dimensions of parental self-evaluation, and it constitutes a cost- and time-effective instrument suited for at-risk mothers.