Youth-staff relationships and program activities are important elements in designing high-quality afterschool activities that promote a broad range of outcomes. Using a qualitative approach, Latinx adolescents were interviewed (n = 28, 50% girls) about their experiences in a university-based afterschool math enrichment activity. Findings under the first goal of the study suggest that Latinx adolescents perceived changes in their math-specific outcomes (e.g., problem-solving skills), future science, technology, engineering, and mathematics (STEM) pathways (e.g., envisioning a future career), and social-emotional skills (e.g., relationship skills) as a result of participating in the activity. Under the second goal of the study, findings identified the specific practices that adolescents thought promoted those outcomes, including incorporating advanced math concepts and engaging in collaborative learning, engaging in campus tours and informal conversations, and using culturally responsive practices. The findings from this study can be leveraged by scholars and educators to design, further strengthen, and evaluate high-quality afterschool activities.