This doctoral thesis focuses on the role of culture as a variable in student learning, a topic that is often overlooked by STEM educational communities but one that is directly relevant to student engagement and learning outcomes. In 2012 the President's Council of Advisors on Science and Technology (PCAST) reported that a million more STEM professionals in the U.S. workforce were needed over the next decade. Recent reports suggest women in science and engineering have made small gains, while historically underrepresented ethnic groups (Blacks, Hispanics, American Indians) continue to be significantly underrepresented in STEM fields. The lack of diversity continues despite recognition of the disparity and programs to raise awareness of the problem. As the U.S. aspires to retain a leadership role in research and development in an increasingly diverse and globally interconnected society, this disparity is unsustainable. This study examines how different pedagogical approaches shape student outcomes in Astronomy 101 courses. In a comparative study, two pedagogical approaches were analyzed using both quantitative and qualitative methods in a semiexperimental nonequivalent group research design. The theories of culturally responsive pedagogy (CRP), active learning theory in STEM, and Indigenous knowledge systems (IKS) ground this approach. The findings of this study show important gains for all students with striking gains for URM (underrepresented minority) students. URM students who participated in the course with increased culturally responsive pedagogy were exceptionally engaged and learning gains improved significantly. The findings indicate that there is a need for tangible, evidence-based, culture-based curriculum and pedagogy. Research data was collected using the Astronomy Diagnostic Test (ADT v2), Classroom Observation Protocol for Undergraduate STEM (COPUS), and final course grades.