真空蒸馏是一种使待分离液体上方压强小于其蒸汽压的蒸馏方法。这种方法适用于蒸汽压大于环境压力的液体。由于待分离液体沸点降低，真空蒸馏不一定需要加热。

在实验室中，真空蒸馏被用于沸点较高或在温度接近于沸点时容易发生反应的液体。对于温度敏感的物质如β-胡萝卜素等需要通过真空蒸馏进行分离，这样可以防止由于温度变化造成的化学反应。真空蒸馏比普通蒸馏有更少的残留物。

Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure) causing evaporation of the most volatile liquid(s) (those with the lowest boiling points). This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the mixture.