A suite of newly published reports supported by The Wallace Foundation reveals the features and outcomes of high-quality principal learning and exposes disparities in principals' access to strong learning opportunities, especially in high-poverty schools. These reports demonstrate how collaborating institutional partners -- universities, school districts, and state and federal agencies -- can address the gaps to strengthen principal pipelines, and experts on a recent webinar offered insight about how to make those improvements sustained and systemic (The Wallace Foundation, 2022). In 2016, The Wallace Foundation launched the University Principal Preparation Initiative, a multiyear initiative to support seven universities to upgrade their principal preservice training programs in line with research-supported practices. As a group, the selected universities and their partners participated in a common process and had access to supports coordinated and funded by The Wallace Foundation that defined the initiative, including: Quality Measures, a research-based self-assessment tool and process; standards alignment; mentor programs; logic model development; technical assistance; and professional learning communities. This article describes how the initiative expanded access to high-quality learning for principals and access to tools that support program design, implementation, and continuous improvement.