Background: Children living in urban areas often have limited opportunities to experience informal science environments. As a result, some do not have a deep understanding of the environment, natural resources, ecosystems, and the ways human activities affect nature. Purpose: This article examines how experiential science education supported urban children's science knowledge and engagement through cultural relevance and eco-justice during a 1-week summer camp. Methodology/Approach: Third- through sixth-grade children from African American and Latinx urban communities in Colorado participated in a weeklong program using experiential learning opportunities including environmental and climate change lessons, activities at a local community-based site, and field trips to nature- and science-themed sites. Pre- and posttests, focus group interviews, journals, and student work samples were analyzed. Findings/Conclusions: Children's science content knowledge as well as their engagement in science lessons and field trips were positively influenced during the study. Implications: This study provides a template for establishing culturally relevant experiential learning opportunities to engage underrepresented children in science.