High-quality professional development opportunities for teachers are centrally important to improve instructional effectiveness and increase student learning. In particular, professional development is needed to help teachers with the instructional shifts required in implementing the college and career-readiness standards (CCRS). The CCRS require substantially revised instructional materials and shifts in teachers' instructional practices, leading to challenges for teachers in implementing CCRS-aligned instruction. This study examined the experiences of teachers in six schools participating in one of three teacher network programs during the 2016-17 school year. The authors explored participant perspectives on the potential benefits of their engagement with the networks for themselves and their schools. The goal of this research was to provide an in-depth picture that would describe how teachers engage in networks, what they may gain from participation, and how their learning from network programs may spread throughout their schools. This type of evidence is needed to understand which approaches hold particular promise and identify barriers to success that can inform future implementation efforts for both schools and the network organizations. Guided by the logic model, the study included several research questions related to teacher learning opportunities through the network programs. The study used an intentional sampling approach to identify schools and respondents to participate in the cases. Members of the case study team conducted a one-day visit to each selected school during March and April 2017. Overall, findings from the case studies indicated that during their first year of participation in the network programs, core teachers perceived that the network programs provided quality materials and training that was useful. Core teachers reported benefits to their own instruction because of network training and gained instructional leadership opportunities through participation in network programs, especially when provided with explicit training in leadership roles. Respondents also perceived that the support from network programs was aligned to schools' priorities for teacher growth and instruction.