Studies examining the associations between Internet use and social skills are increasingly frequent. However, most of them only evaluate offline social skills and consider them as equivalents to online social skills. So far, no instrument allowed differentiating social skills depending on online versus offline contexts. This study aimed to develop and validate the Real and Electronic Communication Skills questionnaire (RECS), a new measure evaluating several dimensions of social skills in two different contexts (i.e., face-to-face and computer-mediated communication). Results of exploratory and confirmatory factor analyses among a sample of 657 adolescents and young adults (mean age = 17.68 years; 67% female) showed that the best fitting model for each context is a bifactor solution, with one general factor (Social Competence) and four specific factors (Sociability, Emotion Decoding, Disclosure, and Assertiveness). Each specific factor was differentially correlated with theoretically relevant subscales of the Social Skills Inventory, confirming the external validity of the RECS. The RECS is the first instrument allowing not only to assess social competence in online settings but also to quantify the relationships between offline social skills and their online counterpart. Given its ease of use and brevity, the RECS is a useful and promising instrument to capture social skills in both online and offline contexts.