We synthesizes the major factors and economic consequences of the tax avoidance research from the accounting, finance, and economics literature. We survey the evidence in four main areas: (1) the reasons firms avoid income taxes; (2) the micro-level influencing factors of tax avoidance; (3) the macro-level influencing factors of tax avoidance. (4) the economic consequences of the tax avoidance. Finally, we propose important directions for future research.