Physical activity stimulates the nervous system and subsequently increases cognition, neural functioning, and information processing in the human brain (Colcombe, Kramer, Erickson, Scalf, & McAuley, 2004; Erickson, Voss, Prakash, Basak, & Szabo, 2011). Students who include athletic pursuits in their daily schedules tend to perform better academically than those who do not, despite the need for them to make difficult decisions about how to handle the increased demands on their time and how to prioritize their efforts (Fedewa & Ahn, 2011). Some researchers suggest that participation in athletics improves the overall school experience for college and university students, because student-athletes develop skills and tools for learning in various challenging situations (Guan, Xiang, McBride, & Keating, 2013; Sauer, Desmond, & Heintzelman, 2013). Unfortunately, members of underrepresented groups in science, technology, engineering, and mathematics (STEM) fields often experience learning disadvantages due to negative stereotypes of teachers and instructors (Beamon, 2014; Comeaux, 2011; Harper & Davis, 2012; Harris, Hines, Kelly, Williams, & Bagley, 2014). However, athletics offers more opportunities for learning and may provide these students with avenues for academic success. This study examined student's scores on state-mandated, standardized tests in STEM areas to determine if participation in athletics influences student achievement for secondary students in Pennsylvania. The study found that student-athletes outscore their non-athlete peers on nearly every test measure. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]