Tax avoidance imposes substantial fiscal costs on emerging economies, and corporate governance is conventionally viewed as a primary internal constraint on aggressive tax planning. Yet the empirical relationship between governance and tax avoidance in emerging markets is considerably more complex and context-dependent than this conventional view suggests. This article synthesizes recent cross-country evidence on how board characteristics, ownership structure, financial reporting quality, and country-level institutions jointly shape corporate tax avoidance in emerging economies. Using a systematic thematic review of studies published between 2019 and 2026 spanning Pakistan, Mexico, Iran, Morocco, Jordan, Indonesia, Malaysia, Nigeria, Egypt, China, Greece, and South Africa, the analysis finds that board independence and board size generally reduce tax avoidance, but these effects disappear entirely in some institutional contexts, most notably Greece. Ownership structure shows an even more divided pattern: family and concentrated ownership are associated with greater tax avoidance in several markets, consistent with private-benefit expropriation rather than effective monitoring, while state ownership curbs avoidance where reputational and political accountability incentives are salient. Financial reporting quality and audit quality consistently moderate governance's effectiveness, and country-level institutional quality independently reduces tax avoidance across a broad cross-country sample. The synthesis concludes that corporate governance's capacity to constrain tax avoidance in emerging markets is conditional on institutional enforcement strength and ownership concentration, such that identical governance structures can produce opposite effects depending on the surrounding institutional environment