The underrepresentation of women and minorities in the science, technology, engineering, and mathematics (STEM) fields is a major concern for researchers, policymakers, and educators. Many causes of this issue have been identified over the years. However, effective methods for increasing minorities' and women's participation in STEM may still be limited. This study examines the role that identity formation plays in encouraging rural African American girls to pursue STEM education, utilizing data from an informal science enrichment program that targets STEM underrepresented middle school-aged students from rural communities. A qualitative design was employed to examine rural African American middle school-aged girls' science interests, attitudes, and identities often referred to as affinities. Qualitative data included observations, artifacts, and individual interviews. The study is presented in two components: participant affinities and science identity formation. Participants had high or sustained affinities for science as compared to their initial program entry. Analysis of qualitative data of science affinities revealed several emergent themes discussed center around rural, African American middle school-aged girls' interests in science, attitudes toward science, and elements of science identities. Types of emergent science themes developed in this study (e.g., understanding, support/engagement, and career aspirations) inform different ways in which rural, African American middle school-aged girls engage with science and informal science learning. Implications for best practice in nurturing science engagement and identities in African American middle-school-aged girls include the importance of hands-on science activities, the need for energetic, relatable scientific-career role models, and an emphasis on deep understanding of scientific principles. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]