The aim of this study is to investigate the effect of mind and intelligence games on critical thinking tendencies and decision-making skills of third grade primary school students. In this study, pretest-posttest control group model, one of the quasi-experimental designs within the scope of quantitative research methods, was used. The research was conducted with the participation of 48 third grade primary school students. "The Critical Thinking Dispositions Scale for Elementary School Students" and "Marmara Decision Making Skills Perception Scale for Primary School Students" were used as data collection tools. The data obtained were analyzed using a statistical package program. According to the analysis results, while there was no statistically significant difference between the pre-test and post-test scores of the control group, it was determined that there was a statistically significant difference between the pre-test and post-test scores of the experimental group in which mind and intelligence games training was given. In addition, when the posttest scores of the experimental group and the control group were compared, it was seen that there was a statistically significant difference in favor of the experimental group.