This document discusses mainstreaming climate-smart agriculture (CSA) in national programs and policies in Africa. It presents a framework for integrating CSA across different scales, from the African Union and regional economic communities down to farming systems and program implementation. It introduces the CSA-Plan, a multi-step planning and implementation guide to help scale up CSA. The CSA-Plan includes steps for stakeholder engagement, capacity development, developing CSA investment portfolios, programming design, implementation guidelines, and monitoring and evaluation. Examples of tools used in the CSA-Plan process are also presented.