The aim of this study was to compare ninth-grade students' states of self-esteem and decision-making with regard to their levels of physical activity. A total of 374 students, of whom 205 were female and 169 were male (x([subscript age])=15.22±0.414), selected by convenience sampling from four different high schools determined by purposive sampling, participated voluntarily in the study. The research was designed in the general survey model as a causal-comparative study. In the study, the "Personal Decisiveness Scale" (PDS), "Self-Esteem Scale" (SES), "International Physical Activity Questionnaire" (IPAQ, short form) and Personal Information Form were used as data collection tools. In the data analysis, one-way ANOVA (Tukey), Kruskal-Wallis H test, 2x3 MANOVA and Pearson correlation analysis were used. Type 1 error was set to 5% (a=0.05). Exploratory indecisiveness and impetuous indecisiveness scores were found to be highly positively correlated, while both indecisiveness scores were found to be moderately positively correlated with self-respect. Regarding physical activity levels, levels of self-esteem among the Science High School students were found to be significantly higher in the HEPA (health-enhancing physical activity) group than in the inactive and minimally active groups. It was determined that students at the Social Sciences High School had lower self-esteem scores and higher impetuous indecisiveness scores than students from all the other high schools, and that they had higher exploratory indecisiveness scores than students from the Science High School. Students who engaged in regular physical activity had higher levels of self-esteem than those who did not, while females had higher levels of exploratory indecisiveness than males. Exploratory indecisiveness scores were found to be significantly lower among those who engaged in team sports compared to those who did individual sports. In conclusion, regarding the negative relationship between indecisiveness and self-esteem, it can be said that high levels of physical activity increase the self-esteem of students at higher academic levels, that students in Social Sciences High Schools need to be supported with more physical activity, and that females and those doing individual sports have higher levels of exploratory indecisiveness.