The self-reporting of social skills continues to be assessed through the assertiveness inventories developed in the 1970s, such as the Rathus Assertiveness Schedule (RAS), the Assertion Inventory (AI), and the College Self-Expression Scale (CSES). The study reported here involved 421 university students (76.5% women) and obtained the factor structures of the aforementioned instruments, plus the new Social Skills Questionnaire (SSQ-I) (Cuestionario de habilidades sociales, CHASO-I). The factorial solutions obtained were 6, 8, 11 and 12 factors, respectively. The reliability (Guttman split-half and Cronbach α) of all the questionnaires was high, and the correlations between the CHASO-I and all the other questionnaires were moderate. The sex differences found involved the total scores of the RAS and the factors “Speaking or performing in public/Interacting with figures in authority”, “Interacting with persons I am attracted to”, and “Interacting with strangers”, with men being more skilled than women, and the factor “Apologizing/Recognizing their own mistakes”, with women being more skilled than men. The study concluded by recognizing certain common problems affecting the self-report measures of social skills, as well as certain advantages of the new CHASO-I.