Adults are skilled at using language to construct/negotiate identity and to signal affiliation with others, but little is known about how these abilities develop in children. Clearly, children mirror statistical patterns in their local environment (e.g., Canadian children using "zed" instead of "zee"), but do they flexibly adapt their linguistic choices on the fly in response to the choices of different peers? To address this question, we examined the effect of group membership on 7- to 9-year-olds' labeling of objects in a trivia game, exploring whether they were more likely to use a particular label (e.g., "sofa" vs. "couch") if members of their "team" also used that label. In a preregistered study, children (N = 72) were assigned to a team (red or green) and were asked during experimental trials to answer questions--which had multiple possible answers (e.g., "blackboard" or "chalkboard")--after hearing two teammates and two opponents respond to the same question. Results showed that children were significantly more likely to produce labels less commonly used by the community (i.e., dispreferred labels) when their teammates had produced those labels. Crucially, this effect was tied to group membership, and could not be explained by children simply repeating the most recently used label. These findings demonstrate how social processes (i.e., group membership) can guide linguistic variation in children.