This study investigated moderating effects of classroom friendship network structures (centralization and density), teacher-student attunement on aggression and popularity, and gender on changes in the social status of aggression over 1 school year. Longitudinal multilevel analyses with 2 time points (fall and spring) were conducted on a sample of 856 fourth and fifth graders from 45 classrooms. Aggressive boys lost social status over time in classrooms where friendship networks were egalitarian (not centralized) and dense (with many friendship ties) and where the teacher and students were attuned to (shared perceptions about) who in their classroom was aggressive and popular. There were no effects for girls. Educational implications and prospects for setting-level theory, measurement, and intervention are discussed.