The purpose of this study was to investigate the interplays among the critical thinking disposition, cognitive flexibility, math anxiety and math achievement with structural equation modeling and determine the degree of the mediating effect of math anxiety in primary, middle and high schools. Within the scope, we also focused on the predicting variables of math achievement and compared the general tendency of these variables by gender, school type and grade level. The participants of the study were 1628 students from grades 4, 8 and 12. While critical thinking disposition and cognitive flexibility had a significant and positive effect both among themselves and on math achievement, math anxiety had a significant and negative effect on all these variables in the models. Although math anxiety has a partial mediating effect on math achievement at middle school and high school levels, it shows no such effect in primary school.