Ecosystem restoration, guided by numerous principles and practical guidelines, has been hailed as a strategy to combat climate change, reduce global biodiversity loss, restore ecosystem services, and enhance human well-being. Yet, translating restoration principles into practice remains challenging for policymakers and practitioners. To address this issue, we identify five frontiers for advancing ecosystem restoration in East Africa's forest landscapes, using western Rwanda as a case study. Instead of drawing on existing high-level ecosystem restoration guidelines, we synthesized locally grounded insights into tangible restoration priorities. We conducted a full-day multi-expert workshop using a “world café” approach to facilitate participatory large-group discussions, involving scientists, practitioners, and decision-makers working on ecosystem restoration in Rwanda. Five critical frontiers for ecosystem restoration science and practice were identified: (i) defining ecosystem restoration goals and elements of success; (ii) embedding ecosystem restoration in the promotion of multifunctional landscapes; (iii) enhancing food security, nutrition, and livelihoods through ecosystem restoration; (iv) engaging with values and nature's contributions to people in ecosystem restoration; and (v) governing ecosystem restoration for equity. For each of these frontiers, we highlight the state-of-the-art, emerging research priorities, and recommendations for practice and policy to move ecosystem restoration ahead.