The Tobin tax is a tax levied on spot currency conversions, with the intention of disincentivizing short-term currency speculation, named after economist James Tobin.

In contrast to a consumption tax paid by consumers, the Tobin tax is meant to apply to financial sector participants as a means of controlling the stability of a given country's currency. It is more formally known today as a Financial Transactions Tax (FTT), or less formally a Robin Hood tax.