This study designed 1) to develop a multidimensional thinking styles scale based on theory of mental self-government for sixth grade student 2) to investigate quality of the developed scale 3) to study profile of styles of sixth grade student and a relation of profile of styles of student in each dimension and background of gender and grade with the group sample of 1,545 sixth grade students from schools affiliated with the Office of Basic Education Commission, Education Department Bangkok Metropolitan Administration, and Office of the Private Education Commission. Thinking styles scale for sixth grade student was utilized in this study and received information was analyzed by using Nominal Response Model (NRM), Confirmatory Factor Analysis and Cluster Analysis. The results revealed that: 1) Thinking styles scale comprised 5 dimensions of function, form, level, scope and leaning with reliability at 0.872, 0.913, 0.722, 0.777 and 0.799 respectively and construct validity by confirmatory factor analysis found that 5 dimensions of thinking styles scale conformed to the empirical data (CFI were 0.918 to 0.975, TLI were 0.919 to 0.988 RMSEA were 0.036 to 0.046 and SRMR were 0.060 to 0.081); 2) The majority of students had judicial styles of function, hierarchical styles of form, local style of level, external style of scope and liberal style of leaning; 3) 96 Profiles of thinking styles be clustered into 3 groups those were Detail Conscious Thinking Procedural Thinking and Achievement Motivation Thinking. The majority of students had Achievement Motivation Thinking; and 4) Thinking styles of students in each dimension related to their background of gender and grade with the level of significance at 0.05.