The assessment and training of social skills constitutes a continuous hot topic both in clinic and research settings. However, social skills assessment has been since its beginnings a difficult area to address. One ongoing issue is that even today self-report instruments for social skills published in the 1970s are still profusely used. The main objective of this study has been to develop a new questionnaire to assess the main dimensions or response classes included in the construct of social skills. The third version of the Social Skills Questionnaire (CHASO-III), comprising 76 items, was administered to 826 participants from various Spanish regions. The exploratory factor analysis yielded 10 coherent factors with little overlap between them. The best four items from each factor were selected in order to establish the final version of the CHASO. The psychometric properties obtained for this final version, including its internal consistency, its reliability and its validity, were very adequate, thus offering a new and updated social skills self-report instrument.