Abstract: Users are fundamental to HCI. However, little is known about how HCI education introduces students to working with users, particularly those different from themselves. To better understand design students’ engagement, reactions, and reflections with users, we investigate a case study of a graduate-level 10-week prototyping studio course that partnered with a children’s co-design team. HCI students participated in two co-design sessions with children to design a STEM learning experience for youth. We conducted participant observations, interviews with 14 students, and analyzed final artifacts. Our findings demonstrate the communication challenges and strategies students experienced, how students observed issues of power dynamics, and students’ perceived value in engaging with users. We contribute empirical evidence of how HCI students directly interact with target users, principles for reflective HCI pedagogy, and highlight the need for more intentional investigation into HCI educational practice.