冷阴极荧光灯管（英文：Cold cathode fluorescent lamp，缩写：CCFL）是一种光源，使用高压电激发水银蒸汽产生紫外线，然后紫外线激发管内的荧光涂层以发出可见光。其原理和霓虹灯有相似之处，只是内部封入的气体不同及有无荧光涂层。

冷阴极灯管通常利用逆变器产生较高的电压，达到气体放电所需的电压。因为电压较高、同功率下的电流相对较低，因此温度较低、寿命也较长。

早期液晶显示器都使用冷阴极荧光灯管作为背光组件，同时一些机箱改造者也会使用。

在相同的照明需求下，CCFL的汞使用量比T5灯管更少，又具备有耐点灭及寿命长的优点，而且光衰很少（不会因为长期使用而减低亮度）；缺点则是效率较差、而且点亮后要一段时间才达到最佳亮度。

A cold cathode is a cathode that is not electrically heated by a filament. A cathode may be considered "cold" if it emits more electrons than can be supplied by thermionic emission alone. It is used in gas-discharge lamps, such as neon lamps, discharge tubes, and some types of vacuum tube. The other type of cathode is a hot cathode, which is heated by electric current passing through a filament. A cold cathode does not necessarily operate at a low temperature: it is often heated to its operating temperature by other methods, such as the current passing from the cathode into the gas.