Recent debate has focused on the desirability of imposing an oil import fee or some broader tax on oil consumption in order to finance tax reform or for some other purposes. Optimal taxation requires that the government raise revenue using the tax instrument with the lowest efficiency cost per dollar of additional revenue. A highly stylized but conventional general-equilibrium model is used to evaluate the magnitude of this marginal efficiency cost for taxes on oil imports, oil consumption, and, as a reference for comparison, labor income.