Stream metabolism measures inputs, movements, and transformations of carbon in flowing water, integrating several ecosystem processes and characterizing overall stream ecosystem health. Advances in monitoring and computing methods allow researchers to assess stream metabolism and influential factors by utilizing continuous measurements and sophisticated modelling approaches. Many aspects of stream metabolism, however, remain unresolved, including the influence of hydrology and hydrologic alteration. To identify key knowledge gaps, we undertook a systematic quantitative literature review (SQLR) of stream metabolism, hydrology, and modelling. Preliminary findings suggest that while reach-scale metabolism in the main channels of perennial systems has received considerable attention, metabolism at network scales, within floodplains and hyporheic zones, or in relation to flow intermittency, and climate and land use change, remains poorly quantified. We also identified case studies that demonstrate how deterministic models have expanded our understanding of hydrology and metabolism under the influence of anthropogenic change. Our SQLR points to the importance of high-frequency monitoring and mechanistic modelling to discern the interplay of hydrology and stream metabolism within and between river systems in a changing world.