In the face of increasingly complex global challenges, many philanthropic funders are reflecting on how to create transformational, systems-level impact. To help answer this question, Rockefeller Philanthropy Advisors, Porticus, and the Skoll, Ford, Draper Richards Kaplan Foundations, launched the Scaling Solutions toward Shifting Systems initiative in 2016. The initiative rebranded in 2021 to become the Shifting Systems Initiative and representation now includes Jasmine Social Investments and Chandler Foundation. The initiative mission remains consistent with our 2016 launch goals: to examine when, how, and why certain solutions achieve system-level shifts, and to share the lessons and recommendations from those successes.