This article expands research on normative school transitions (NSTs) from elementary to middle school or middle to high school by examining the extent to which they disrupt structures of friendship networks. Social network analysis is used to quantify aspects of connectedness likely relevant to student experiences of social support. Data were drawn from 25 communities followed from sixth to ninth grades. Variability in timing of NSTs permitted multi-level longitudinal models to disentangle developmental effects from transition effects. Results indicated that friendship networks were most interconnected in smaller schools and among older students. Beyond these effects, transitions from a single feeder school to a single higher level school were not associated with changes in friendship patterns. Transitions from multiple feeder schools to a single higher level school were associated with diminished friendship stability, more loosely connected friendship networks, increased social distance between students, and friendship segregation between students who formerly attended different schools.