Structural transformation has resulted in an increasing share of services in aggregate value added in advanced and developing countries across the world. We analyze the impact of this shift into services on countries’ efficiency in collecting the value-added tax (VAT). The analysis is based on two alternative measures of VAT efficiency: (1) the VAT C-efficiency, using a broad panel of 134 countries over the period 1970-2014; and (2) the VAT gap using a more granular, proprietary dataset that draws on the results of IMF’s Revenue Administration-Gap Analysis Program covering 24 countries over the period 2004-2016. We find that a higher share of services in aggregate value-added reduces the VAT efficiency, and that this adverse effect is mainly a result of a rise of non-tradable services, which in turn contributes to a narrowing of the VAT base.