This study investigated the factors that are directly and indirectly related to collaborative problem-solving skills of students in Türkiye with multiple and multilevel mediation models, according to PISA 2015 results. The PISA 2015 Türkiye sample consisted of 5895 students. After missing data assignment and outlier analysis, the analyses were performed over the data set of 5882 students. In this study, whether the variables of valuing teamwork and valuing relationships show a mediation effect was tested with the Bootstrap method through multiple mediation models constructed with the dependent variable of collaborative problem-solving and the independent variables of school belonging and disciplinary climate. Our analyses revealed that the mediator variables had significant effects between school belonging and collaborative problem-solving. Similarly, the mediation effect between the disciplinary climate and the collaborative problem-solving was also significant. Multilevel mediation models constructed with the independent variables of students' behavior hindering learning and extracurricular creative activities were analyzed with the multilevel structural equation modeling. The findings indicated that the variables of valuing relationships and valuing teamwork did not have a significant mediation effect between extracurricular creative activities and collaborative problem-solving scores. Similarly, it was found that the mediation effect between the students' behavior hindering learning and collaborative problem-solving scores was not significant. In light of all these findings, it is recommended that school practices be strengthened to improve students' sense of belonging to school and a positive disciplinary climate, to develop students' collaborative problem-solving skills, and to improve attitudes towards collaboration.