The National Writing Project (NWP) is a network of professional development sites focusing on the improvement of writing across schools and communities. Its origins as the Bay Area Writing Project led to a professional development model of teachers teaching teachers, a concept that hinges upon recognition of teachers’ knowledge and their capacity to become leaders within their professional community. In the ensuing years, with early financial support from the US government in the form of an initial grant and an eventual direct federal line item, the NWP expanded from one location to over 200 local sites across the USA’s 50 states and territories as well as international sites. These US and international sites, created in partnership with local universities or colleges, offer localized support to teachers of writing. The project’s model involves an intensive summer institute in which teachers spend their time writing, reading, and sharing their knowledge about writing practices and teaching. While its focus is on the teaching of writing across all levels and disciplines, the project has become a model example of a professional learning and development network. As such, the NWP has created a legacy in teacher learning and development that many within the field of teacher professional development wish to emulate. An examination of this history, highlighting the project’s beginnings within the Bay Area Writing Project and its eventual expansion, speaks to the vision that has driven its success.