Collaborative problem solving (CPS) has been considered as one of the vital 21st century skills. To be successful in CPS requires not only CPS skills but also positive attitudes towards collaboration (i.e., collaboration dispositions). However, the relationship between CPS skills and collaboration dispositions has not been studied much, especially among early adolescent students. The purpose of this study is to investigate the dimensions of students' collaboration dispositions and their relationship to students' assessed CPS skills (i.e., social and cognitive skills of CPS, see Hesse et al., [2015]). Data were collected from 214 Finnish sixth-grade students (Meanage = 12.44, SDage = 0.32, female = 116, 54.21%) in 2019. Students' CPS skills were assessed based on the log file data collected from student pairs' participation in four tasks in a computer-based assessment environment. Collaboration dispositions were measured through a self-report questionnaire. Exploratory factor analysis was applied to investigate the dimensions of students' collaboration dispositions. In addition, analysis of variance was utilised to examine the dimensions of students' collaboration dispositions across their diverse social and cognitive CPS skills. Three dimensions of students' collaboration dispositions were identified, namely, negotiation, advocate/guide and cooperation. Further, we found that the early adolescent students’ CPS social skills, but not cognitive skills of CPS, were associated with their perceived collaboration dispositions. Based on our results, we argue that it is crucial to provide systematic and rigorous interventions and/or models to pay attention not only to integrating CPS skills with subject studies in schools, but also to make students aware of their collaboration dispositions.