风险厌恶 （或风险趋避或风险规避, 英语：risk aversion）是一个经济学、金融学和心理学的一个概念，用来解释在不确定状况下消费者和投资者的行为. 风险厌恶是一个人接受一个有不确定的收益的交易时相对于接受另外一个更保险但是也可能具有更低期望收益的交易的不情愿程度. 例如，一个风险厌恶的投资者可会选择将他的钱存在在银行以获得较低的但确定的利息，而不愿意将钱用于购买股票，在获得高的期望收益的同时承担损失的风险。与一个人的风险厌恶程度相对，称之为「风险容忍」（risk taker）.

In economics and finance, risk aversion is the behavior of humans (especially consumers and investors), when exposed to uncertainty, to attempt to reduce that uncertainty. It is the reluctance of a person to accept a bargain with an uncertain payoff rather than another bargain with a more certain, but possibly lower, expected payoff. For example, a risk-averse investor might choose to put his or her money into a bank account with a low but guaranteed interest rate, rather than into a stock that may have high expected returns, but also involves a chance of losing value.