External data has become an indispensable pillar in state-of-the-art decision-making and value creation in an enterprise context. Despite the increasing motivation to use external data, information systems (IS) research still lacks an adequate data sourcing perspective. This study aims to address this gap by investigating the practical challenges in this emerging field and developing a reference process for sourcing and managing external data. To this end, we adopt a design science research approach leveraging collaboration with practitioners from nine high-profile companies. Our findings contribute to the scarce body of knowledge on data sourcing in IS by proposing explicit prescriptions in the form of a reference process for sourcing and managing external data.