系统性风险（Systematic risk）又称市场风险或不可分散风险，是影响所有资产的、不能通过资产组合而消除的风险。这部分风险是由那些影响整个市场的风险所引起的，例如：战争、政权更迭、自然灾害、经济周期、通货膨胀、能源危机和宏观政策调整。

无论怎样分散投资，也不可能消除系统性风险。避免集中投资於单一市场可减少系统性风险。单项资产、证券资产组合或不同公司受系统性风险影响不一样，系统性风险的大小通常用beta系数（ 系数）来衡量。

In finance and economics, systematic risk (in economics often called aggregate risk or undiversifiable risk) is vulnerability to events which affect aggregate outcomes such as broad market returns, total economy-wide resource holdings, or aggregate income. In many contexts, events like earthquakes and major weather catastrophes pose aggregate risks—they affect not only the distribution but also the total amount of resources. If every possible outcome of a stochastic economic process is characterized by the same aggregate result (but potentially different distributional outcomes), then the process has no aggregate risk.