This article describes a summer enrichment science, technology, engineering, and mathematics (STEM) camp for African-American girls and young women aimed at addressing mathematical and science self-efficacy and reinforcing the importance and usefulness of mathematics and science with a socially transformative curriculum. The research questions guiding this study are: (1) How do African-American girl participants describe their experiences in Girls STEM Institute (GSI)?; and (2) How does the STEM program experience affect their mathematics and science self-efficacy and valuing of mathematics and science? The data, which included journal entries and interviews, were collected and analyzed from four participants and indicated that participating in the Girls STEM Institute led to improved mathematics and science self-efficacy and increased perceptions of the value of science and math knowledge.