Taxation in the upstream oil and gas industry is uniquely structured due to the strategic nature of hydrocarbons, high capital intensity, long project life cycles, and state ownership of natural resources. In Indonesia and many other jurisdictions, upstream activities operate under special fiscal regimes—most notably the Production Sharing Contract (PSC)—which integrate taxation, cost recovery or gross split mechanisms, and government take. Understanding upstream taxation is therefore essential for finance, accounting, tax, commercial, and regulatory professionals to ensure compliance, optimize fiscal outcomes, and manage tax risks throughout the exploration and production lifecycle.