Over the past 15 years, tax reforms have profoundly changed the shape of OECD tax systems and rekindled interest in measuring effective tax burdens. Indeed, in order to understand past reforms or to evaluate the tax policies of particular countries, it is necessary to go beyond statutory rates since these sometimes bear little relation to rates actually paid. This paper updates and extends the Mendoza et al. estimates of average effective tax rates (AETRs) and presents new estimates based on modifications to the methodology to make some of the underlying assumptions more realistic. In particular, the assumption that all income from self-employment is capital income is dropped in favour of assuming that the self-employed earn both labour and capital income. This change raises estimates of the AETR on capital and reduces the estimated AETR on labour but does not alter the trends observed in the updated Mendoza et al. estimates. Both sets of estimates show that, on average, the ...