套利（英语：Arbitrage，又称套戥），通常指在某种实物资产或金融资产（在同一市场或不同市场）拥有两个价格的情况下，以较低的价格买进，较高的价格卖出，从而获取低风险的收益。

套利，通常指在某种实物资产或金融资产（在同一市场或不同市场）拥有两个价格的情况下，以较低的价格买进，较高的价格卖出，从而获取丰厚的收益。例如，某支股票同时在伦敦和纽约交易所上市，同股同权，但是在纽约标价10美元，在伦敦却标价12美元，投资者就可以在纽约买进，到伦敦卖出。又比如在货币交易上进行套利，如借入利息较低的货币为融资，买进高息货币以赚取汇差或利差，例如，日圆放款利息长年维持在近乎零的水平，而南非或巴西等国因其通胀严重，利息常年维持在高水平。如果借入日圆来购买南非币或巴西里拉，在不考虑汇差情况下，也能赚取丰厚的利差。

Uncovered interest arbitrage is an arbitrage trading strategy whereby an investor capitalizes on the interest rate differential between two countries. Unlike covered interest arbitrage, uncovered interest arbitrage involves no hedging of foreign exchange risk with the use of forward contracts or any other contract. The strategy involves risk, as an investor exposed to exchange rate fluctuations is speculating that exchange rates will remain favorable enough for arbitrage to be profitable. The opportunity to earn profits arises from the reality that the uncovered interest rate parity condition does not constantly hold—that is, the interest rate on investments in one country's currency does not always equal the interest rate on foreign-currency investments plus the rate of appreciation that is expected for the foreign currency relative to the domestic currency. When a discrepancy between these occurs, investors who are willing to take on risk will not be indifferent between the two possible locations of investment, and will invest in whichever currency is expected to offer a higher rate of return including currency exchange gains or losses (perhaps adjusted for a risk premium).