Technological diversification has been linked to a wide range of phenomena, including financial performance, innovation, product diversification and inter‐organizational relationships. This is the first systematic review of this literature and provides an overview of its historical development and conceptual foundations. It finds that the role of contingency factors impacting the positive relationship between technological diversification and financial performance needs further exploration. Also, it finds that the research on the links between technological diversification and inter‐organizational relationships requires consolidation. This paper suggests three avenues for further research. First, it sets out an agenda for identifying the antecedents of technological diversification. Second, it identifies contextual factors that could shape the relationship between technological diversification and performance. Third, it argues that technological diversification research must engage with contemporary technological and organizational developments such as digital organizations, open boundaries and networks.