Initial teacher education is increasingly happening online, both formally and informally, within networks that are commercial, institutional, governmental, and research-driven. These networks make use of the capabilities of the internet and related technology to better support teachers. The scholarship of teacher learning within online networks can be divided into four main strands: network design, outcomes from network participation, agency within the network of networks, and critical perspectives on online networks of teachers. Online networks are designed environments, and there are design decisions involved in developing different types of teacher network. Research into networked learning provides a common language for talking about these networks that allows for articulation of transferable design principles and comparison between networks. Some studies of networks of teachers are conducted with a focus upon the forms of social support that teachers provide for each other. These studies look to understand the role of online networks within the profession, and to contribute to growing and testing the base of theoretical knowledge about how teachers can be better supported through online networks. There is a growing strand of literature that focuses upon how teacher agency can be developed so that each teacher can take advantage of a world in which online networks are prevalent and can use them to flourish within the profession. Teachers can learn to develop their own professional learning network that makes use of existing online networks. While there is much optimism about the potential of online learning networks to support teachers and serve the profession, there are also perspectives that are critical of the widespread embrace of online networks by teachers and the way in which this development is changing the profession.