<p>Student engagement in math and science courses decreases starting in middle school and continues throughout high school. This lack of engagement results in students taking only the required math and science coursework and not advanced coursework that would help prepare them for future careers in science, technology, engineering, and mathematics fields. Integrated STEM (Science, Technology, Engineering, Mathematics) learning activities may be used to promote student engagement and learning. This experimental design study was conducted with students in grades 3–5 in one mid-sized rural school district in the upper mid-west. Student engagement was analyzed using a pre/post-survey. Modeling analysis measured the extent to which lesson type, integrated STEM lesson or traditional non-integrated lesson, predicted student engagement. Additionally, we examined the extent to which engagement mediates the relationship between lesson type and student learning. Findings from this study indicate that integrated STEM learning activities increased student engagement, which may lead to students taking additional math and science courses in high school and pursuing a future in a high-demand STEM career.</p>