For many decades, most of the decision-making authority in public schools has been vested in individual principals and other administrators. However, new models of collaborative teacher leadership are beginning to emerge, thanks to four trends: 1) evidence on the positive effects of teacher leadership continues to mount, 2) districts and state policies are codifying teacher leadership roles, 3) teacher leaders are becoming more proficient at using educational technology and sharing their expertise through digital media, and 4) researchers are deepening their knowledge about how teachers learn to lead effectively.