AbstractThis qualitative study explored the design and implementation of a humanoid social robot that mediated collaborative interactions among culturally and linguistically diverse kindergarten children in a US school. The robotic mediation was designed to help children have positive interactions with one another. The study was grounded in theories of childhood development, intercultural communication, and culturally responsive pedagogy. Design research and ethnographic qualitative research methods were used to design, test, and improve the robot’s mediation skills over a ten-week period of active use in a real-world classroom setting. Findings describe the challenges we faced in designing robot-mediated interaction activities as well as the solutions we implemented through repeated ethnographic observations, summarized as (1) anticipating children’s communication styles with flexible design, (2) inviting children to participate with personalized, friend-like communication, (3) enhancing engagement with familiar contexts, and (4) embracing language diversity with a bilingual robot.