As African cities continue to experience rapid urbanisation and face escalating climate risks, nature-based solutions offer a critical, yet underutilised approach for advancing urban resilience and the SDGs. In informal settlements—where environmental justice concerns are acute, and many residents lack access to safe sanitation, water (SDG 6) and green space—there is an urgent need to foster more inclusive, sustainable urban environments (SDG targets 11.3 and 11.6). Despite their potential, questions remain about how nature-based solutions can be designed in context-sensitive ways that reflect the unique social-ecological and governance realities of informal settlements, and how they can be effectively scaled beyond pilot project initiatives or isolated household efforts to broader city-wide or regional applications. Defined as actions that protect, sustainably manage, and restore natural or modified ecosystems while addressing key societal challenges, nature-based solutions can deliver a wide array of co-benefits. For instance, urban trees and forests filter harmful pollutants, reduce exposure to extreme heat (related to SDG 13), improve air quality, cognitive functioning, and mental health outcomes (SDG 3.9), slow flood waters and buffer against strong winds (SDG 11.5), support income generation of populations that disproportionately rely on local ecosystem resources (SDG 15.2) and avoid carbon-intensive lock-ins with infrastructure construction (SDG 116). However, implementing green spaces in overcrowded informal areas presents complex challenges, including maintenance, vandalism, overuse, risk of green gentrification, and the need for robust planning and equitable compensation mechanisms where relocation is unavoidable. Focusing on informal settlements in Africa, this chapter explores climate vulnerabilities, typologies of nature-based solutions, the multifunctional benefits of nature-based solutions, barriers to scaling, and cross-cutting guiding principles for effective and equitable implementation. Drawing on empirical case studies from across the continent—based on collaborative research with shack dwellers federations, local governments, NGOs, UN agencies, and academic institutions—I argue that the long-term success of nature-based solutions is contingent not only on ecological and technical considerations but also on inclusive co-design processes, sustained community engagement, multi-stakeholder collaboration, formalised land use arrangements, the application of social and environmental safeguards to mitigate trade-offs, multifunctionality, complementarity, and integration into broader urban planning and policy frameworks.