Formal teacher leadership roles--such as coach and coordinator--have become a standard component of education reform efforts intended to support teachers' instructional improvement efforts. Yet the culture of schools is widely understood to favor autonomy and egalitarianism, suggesting that classroom teachers may be resistant to peer leadership. This study examines how 12 elementary-level teacher leaders negotiate access to classrooms and encourage instructional change in light of teacher resistance. Findings suggest that teacher leaders make concessions that may ultimately limit their impact on instructional improvement. Also, for these positions to contribute to instructional change, teacher leaders require the support of school administrators who offer guidance to teacher leaders and set expectations for teachers with regard to the enactment of teacher leadership roles. (Contains 2 tables and 1 footnote.)