This study utilized data from a national longitudinal study of 277 early adolescent summer camp participants to examine the iterative links between youths’ experiences in two contexts – summer camp and school – and empathy over two years. Using a cross-lagged panel model, the authors examined how the quality of youths’ developmental experiences within each context, defined as a combination of supportive relationships and engaged learning opportunities, were related to youths’ empathy over time. Results showed that 1) higher quality developmental experiences in each context uniquely predicted improvements in empathy; 2) youths’ developmental experiences at camp and school were mutually reinforcing over time; and 3) school experiences partly mediated the effects of camp experiences and vice versa. Results illustrate the value of out-of-school-time contexts for supporting empathy, the importance of developmental experiences across settings, and the need for researchers and practitioners to attend to the ecosystem of social development.