Nitrogen (N) fertilizer supports global food production, but its use and overuse drive emissions of nitrous oxide (N2O), a potent and long-lived greenhouse gas. Understanding the drivers of N2O fluxes remains elusive, making it difficult to predict emissions in time and space and to develop and evaluate ways to lower emissions through management. Major scientific uncertainties underlying the understanding of the drivers of N2O fluxes identified in a workshop of N2O emissions experts include poor process-based understanding of controls on soil N2O emissions in the field; insufficient data to reduce uncertainty in N2O budgets from the field to regional scales, including N2O emission measurements and importantly, field-scale N balances; and high uncertainty in model predictions of soil N2O emissions across environmental and management conditions. To reduce these uncertainties, we present the concept of N2Onet, a global collaborative initiative to accelerate advances in N2O measurement, analyses, and mitigation. N2Onet will serve as an observational network of supersites with multi-scale measurements; a database hub for N2O flux and ancillary data; and a catalyst for community building, information sharing, and training. By coalescing and coordinating the global community of researchers, N2Onet will provide a roadmap for reducing N2O emissions from agriculture worldwide.