This paper provides: (i) the most comprehensive estimates of energy subsidies currently available for 176 countries; and (ii) an analysis of "how to do" energy subsidy reform, drawing on insights from 22 country case studies undertaken by IMF staff and analyses carried out by other institutions. On a "pre-tax" basis, subsidies for petroleum products, electricity, natural gas, and coal reached $480 billion in 2011 (0.7 percent of global GDP or 2 percent of total government revenues). Removing these subsidies could lead to a 13 percent decline in CO2 emissions and generate positive spillover effects by reducing global energy demand.