The current study examined Connect Science, a service-learning program which incorporates social and emotional learning lessons and science lessons developed around Next Generation Science Standards. Guided by Self-Determination Theory, focus groups with 8 Connect Science classrooms and 8 control classrooms investigated fourth graders' experience of autonomy, competence, relatedness, and academic engagement in science. Results of a content analysis indicated that Connect Science students experienced more frequent cognitive autonomy and more positive emotional science engagement than students in control classrooms. However, Connect Science students reported more mixed feelings about relatedness to their peers. Students from both Connect Science and control classrooms reported similar experiences of competence and teacher relatedness. The findings demonstrate that service-learning is a promising practice for facilitating autonomous student experiences and emotional engagement in science while also highlighting the relational challenges of such approaches. We discuss future research directions and recommendations for mitigating such challenges in elementary classrooms. [This paper was published in "Applied Developmental Science" v28 n1 p58-81 2024.]