Regional value chains (RVCs), involving regional lead firms that trade within a single world region, are increasingly prominent within the Global South. Yet, emerging analyses of RVCs have not adequately interrogated how the expansion of RVCs relates to global value chains (GVCs), how actors in RVCs interact with overlapping chains, or the implications for development. Through a case study of horticulture value chains in Kenya, two main types of RVC–GVC interactions are identified. First, opportunistic RVCs emerged when suppliers found their produce rejected from GVCs for lack of standards compliance and began selling spillover produce in regional markets. Second, a more independent targeted RVC has evolved since suppliers began selling produce directly to regional supermarkets that had established their own regional procurement strategies and private standards. Some suppliers are also involved in hybrid interactions – participating in both opportunistic spillovers and targeted RVCs. The analysis concludes that the expansion of RVCs must be considered in the context of GVCs, leading to more nuanced understandings of the characteristics and development implications of RVCs.