The research is aimed to explore the effect of STEM education on the motivations and epistemological beliefs related to science among talented and gifted students. A mixed research method was employed in collecting the data of the research. The sample of the research consisted of 20 5th and 6th grade students who were diagnosed to be talented. Before the activities, the Epistemological Beliefs Questionnaire and the Motivation Scale for Science Learning were applied to the students. The reflective journals were asked to fill in reflective journals after each activity and individual interviews were conducted after all activities were completed. A significant difference was found between the Epistemological Beliefs Questionnaire and the Motivation Scale for Science Learning pre-test and post-test scores at the end of the research. With the conducted interviews and results from the journals, positive changes were observed in students' self-confidence, motivation, and attitudes towards science lessons in training.