Sustainable intensification is receiving growing attention as a way to address the challenge of feeding an increasingly populous and resource-constrained world. But are we asking too much of it? Nearly 20 years after the concept was developed, this briefing revisits the term and asks what sustainable intensification is — a useful guiding framework for raising agricultural productivity on existing arable land in a sustainable manner; and what it is not — a paradigm for achieving food security overall. The paper summarises the history of and controversy surrounding the term, its main assumptions and risks, as well as its value for the future. We call for a rerooting of sustainable intensification as one key element of a sustainable food system situated within a green economy.