Groups exhibit behavioral consistencies similar to individuals, such as making more or less bold decisions or struggling more or less frequently. However, previous research findings focus only on specific dimensions of groups instead of the general structure of group personality. Based on previous research findings on group and team efficiency, we derived two basic dimensions of group personality, group openness and cohesion, representing the group’s outward and inward orientation, respectively. We present the “Group Openness and Cohesion Questionnaire” (GOCQ) as a measure to assess these two group personality dimensions in groups independent of their context. Confirmatory factor analysis confirmed the proposed two-dimensional structure with good to excellent psychometric properties. Evidence of validity is provided through group age, group size, and by the fact that the ratings reflect team characteristics. In general, the results support the conceptualization of these two basic dimensions of group personality and provide first indications of validity of the presented measure GOCQ.