This study aims to investigate the effects of Science Technology Education Math (STEM) practices on academic achievement and motivations of students in the 5th grade of middle school in "Exploring and Knowing the World of Living Creatures" section in Science lecture. The study was designed in a semi-experimental pattern with pre-test post-test control group. A middle school in the center of Antakya was selected by appropriate sampling method. The sample of the study was formed by the 5th grade students who were studied in 2 sections where the same teacher taught. A group of students in one section formed the control group of students while the other branch formed experimental group. The unit 'Exploring and Knowing the World of Living Creatures' was explained through the lesson plans prepared according to the STEM applications in the experimental group and through the methods appropriate to the course book in the control group. As a data collecting tool, both groups were given the "Exploring and Knowing the World of Living Creatures Achievement Test (EKWLCAT) and "Motivation Scale toward Science Learning" (MSSL) were applied. The obtained data were analyzed by statistical analysis utilizing the mean, standard deviation, frequency and percentage values of these data using an appropriate statistical program. As a result, it has been determined that STEM applications have a positive effect on academic achievement. However, when the subcategories of the motivation scale were examined, a statistically significant difference was not found in the subcategories of performance communication and participation, while a positive increase was found in favor of research and cooperation.