As the group of the world’s largest economies and biggest emitters, G20 countries are central to implementing solutions to the climate emergency. This discussion paper assesses to what extent they are setting climate mitigation targets that are ambitious enough and/or meet their fair share of global emissions reductions consistent with limiting global heating to 1.5°C. It applies three different methodologies to assess their pledges. Despite some differences between these methodologies, the paper finds that the G20 countries – both collectively, and almost all of them individually – are failing to achieve their fair share of ambitious global mitigation required to limit global heating to 1.5°C, regardless of which assessment methodology is applied. Additionally, the assessment shows that the high-income G20 member countries are pledging to do a much smaller fraction of their fair share as compared to the middle-income countries.