The aim of this study is to examine the causal relationships between high school students' inquisitiveness, open-mindedness, causal thinking, and rational and intuitive decision-making dispositions through an assumed model based on research data. This study was designed in correlational model. Confirmatory factor analysis and path analysis, which are structural equation modelling applications, were used to explain these relationships. The participants were 404 students studying in five high schools in Usak province. Critical Thinking Dispositions Scale developed by Yucel and Ulucinar (2013) was used to identify the high school students' inquisitiveness, open-mindedness and causal thinking dispositions. As for identifying rational and intuitive decision-making dispositions, an adaptation of the decision-making inventories by Scott and Bruce (1995) and Bachard (2001) was employed. The findings of the study show that inquisitiveness and open-mindedness dispositions directly affected casual thinking. In addition, causal thinking was found to have an effect on rational decision-making and intuitive decision making dispositions.