Supporting STEM Learning Opportunities Act This bill establishes a grant program to promote hands-on learning opportunities in science, technology, engineering, and mathematics (STEM) education for prekindergarten, elementary, and secondary school students. Specifically, the National Science Foundation must provide grants to eligible nonprofit programs to (1) support hands-on learning opportunities in STEM education, including through after-school activities and innovative learning opportunities (e.g., robotics competitions); and (2) evaluate the impact of these programs on STEM learning and disseminate the evaluation results.