||To address climate change (CC) in eastern and southern Africa (ESA) will require accelerated development and dissemination of crop varieties with climate-smart (CS) traits over the coming decades. However, investment in crop improvement and rates of variety turnover are currently extremely low in the region. Smallholder farmers, who generate the bulk of agricultural output in ESA, continue to cultivate old crop varieties that lack CS traits such as drought tolerance and resistance to new and emerging pests and diseases. The emergence of the private seed sector in ESA provides a unique opportunity to complement established public crop improvement programmes, and accelerate development and dissemination of CS crop varieties through scalable, certified seed systems. This chapter will discuss; the growth of the private seed sector since the seed industry in ESA was deregulated, the importance of public-private partnerships in driving genetic gains for CS traits, and the importance of developing a favourable regional regulatory environment that incentivises the private sector to rapidly scale out CS crop varieties (and withdraw obsolete varieties).