This paper reviews the rapidly growing empirical literature on international tax avoidance by multinational corporations. It surveys evidence on main channels of corporate tax avoidance including transfer mispricing, international debt shifting, treaty shopping, tax deferral and corporate inversions. Moreover, it performs a meta analysis of the extensive literature that estimates the overall size of profit shifting. We find that the literature suggests that, for the most recent year, a 1 percentage-point lower corporate tax rate compared to other countries will expand before-tax income by 1.5 percent-an effect that is larger than reported as the consensus estimate in previous surveys and tends to be increasing over time. The literature on tax avoidance still has several unresolved puzzles and blind spots that require further research. JEL-Codes: F230, H250. participants at the IMF "Evaluating Tax Reform" conference and Fiscal Affairs Department seminar for helpful comments. We are grateful to Jost Heckmeyer and Michael Overesch for sharing their dataset for replication purposes. Any remaining errors are our own. 5 Taxes in high-tax locations can also be avoided by changing the location of foreign direct investment (FDI). This paper, however, focuses only on tax avoidance through profit shifting, not through a change in the location of real capital (for a survey of taxation and FDI, see e.g. De Mooij and Ederveen 2008). 6 Transfer mispricing has also implications for national accounts statistics and the measurement of GDP growth, see e.g. Guvenen et al (2017).