This study examines what occurs when principals of urban schools meet together to learn and improve their instructional leadership in collaborative principal networks designed to support, sustain, and provide ongoing principal capacity building. Principal leadership is considered second only to teaching in its ability to improve schools, yet few principals entering the principalship have the skills and capacities to meet the myriad challenges that face urban, economically disadvantaged schools. Too often, principals are left without meaningful support and ongoing learning opportunities that continue to develop them into the instructional leaders needed to address today's achievement gap. Networking potentially bridges these needs by providing ongoing professional development for principals in collaborative settings. The sample studied was one network of fifteen principals and their facilitator in San Antonio, Texas. I used principal and facilitator interviews, six meeting observations, and shadowing of four sampled principals to describe principal learning experience, key factors that influence networking, and who benefits from network participation. My findings show network focus on student achievement increases principal experience of instructional leadership learning. Principals need focused learning in collaborative settings that engender trust and the formation of collegial relationships. They also prefer meeting with other principals who share a value of learning and represent diverse perspectives. Principals in the network increased their use of teacher teams, applied data-based approaches to improve student achievement problems, changed their classroom supervision practices, implemented texts used during networking with their teachers, and increased their engagement of faculty in tough conversations about practice. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]