风险评估（英文：Risk Assessment），是风险管理的一个重要过程，风险管理国际标准ISO31000定义风险评估的过程为：风险评估是风险识别、风险分析及风险评价的全过程。在国际标准ISO31010 风险管理——风险评估技术中，明确给出了风险评估过程需要解决的5个基本问题：

而表示风险的方法则为：经常用一个事件的后果（包括情况变化）和对应的发生可能性这二者的结合来表示风险。风险的定义已经发生了颠覆性的改造，摆脱了传统管理思维中定义风险为纯损失的模式，从而直接改变风险管理的方式：降低损失，最大化机遇。

Risk assessment is the determination of quantitative or qualitative estimate of risk related to a well-defined situation and a recognized threat (also called hazard). Quantitative risk assessment requires calculations of two components of risk (R): the magnitude of the potential loss (L), and the probability (p) that the loss will occur. An acceptable risk is a risk that is understood and tolerated usually because the cost or difficulty of implementing an effective countermeasure for the associated vulnerability exceeds the expectation of loss. "Health risk assessment" includes variations, such as risk as the type and severity of response, with or without a probabilistic context.