This study used mixed methods to compare perceptions of relational aggression (RA) of adolescent girls (n = 282) and their teachers (n = 15) in New Zealand, and to explore strategies for teachers to effectively manage RA in the classroom. Results indicated that younger adolescent girls view physical aggression as more acceptable than older girls, and that the girls were more likely to view others as engaging in RA, rather than themselves. Teachers' perceptions of RA behaviours overlapped with those of the girls' but perceptions of effective strategies varied. The results led to the development of a model that identifies three types of relationally aggressive adolescent girls. Results are discussed in terms of applying the model and developing strategies for building healthy relationships. (Contains 3 tables and 1 figure.)