Multiple opportunities exist for mitigating greenhouse gas emissions on livestock farms. However,prioritising mitigation measuresin policy isproblematic because of the fragmentary nature of the evidence-base on abatement potentials and the heterogeneous nature of the industry. Limited literature exists on the abatement potential of sheep farm-specific mitigation measures and livestock measures applied in a sheep farm setting. This study augments the evidence-base on mitigation opportunitiesfor sheep systems in England and Wales through: estimating the cradle to farm gate greenhouse gas emissions of 64 sheep farms and assessing the relationship between farm variables and carbon footprint at the multi-farm level; producing a short-list of practical and effective mitigation measures based on the opinionsof experts and farmers derived through Best-Worst Scaling surveys; developing marginal abatement costcurves for a case-study lowland, upland and hill sheep farm,indicating the abatement potentials and cost-effectiveness of short-listed mitigation measures. The results convey two primary messages for industry and policy decision-makers: firstly the importance of productivity and efficiency as influential drivers of emissions’abatement in the sector, particularly the cost-effective measures improving ewe nutrition to increase lamb survival and lambing as yearlings; and secondly,the need for policy instruments to acknowledge and account for heterogeneity within the industry. Instances of heterogeneity include variation in farmer perceptions of the practicality of sheep breeding measures according to farm size and type, and differences in the abatement potential of individual measures linked to current farm management. It is suggested that productivity and efficiency targets could be communicated to farmers through the use of productivity benchmarks, and that the construction of further case-study farm marginal abatement cost curves could allow guidelines to be developed which define the management scenarios and conditions in which each measure is most effective. Case-study farm-level marginal abatement cost curves are advocated asapotential tool toinform farm-level mitigation strategyin addition to refining higher-level policy.