Recently, potential effects of STEM activities on students in science education are among important research topics. Therefore, in this study, the effect of STEM activity practices on the scientific creativity of middle school students was investigated. The research sample consists of 98 (experimental group = 50 students, control group = 48 students) eighth grade students studying at a state secondary school in the 2018-2019 academic year. The research is a pre-test post-test control group quasi-experimental design. While teaching with STEM activities was applied to the experimental group, the content of the science implementations course curriculum was applied to the control group. During the implementation process, the groups were not affected by each other and the lesson times were treated equally in all groups. The data of the study were obtained with the "Scientific Creativity Test" and evaluated with the t-test. When the research results are examined; It was determined that there was a significant increase in the scientific creativity test results of the experimental group compared to the control group, and according to these results, it can be said that the STEM activity practices in the study contributed to the scientific creativity of the students. However, when the scientific creativity test fluency, flexibility and originality sub-scores of the experimental and control groups were evaluated, it can be said that the results differed significantly in favor of the experimental group.