乘波导引是军事上一种控制武器运动的导引方式，通常是使用在各种飞弹系统上，作为导引的信号以雷达或雷射为主，是一种较为简单的导引方式。

乘波导引常被列为指挥导引的一类，事实上，两者有相当的差异；指挥导引飞弹内的导引系统只需运行接收命令的工作，而乘波导引的飞弹则还要传感其在波束中的位置，从而指导飞弹保持在波束中央。

发射载具在标定目标之后，将雷达发射的导引信号持续照射在目标上，发射载具或者是提供导引信号的雷达必须配合目标的移动而保持波束的位置。飞弹发射之后会进入导引波束当中，如同跟随一条看不见的线路飞行，而在这个线路的末端就是飞弹要攻击的目标。

Beam-riding, also known as Line-Of-Sight Beam Riding LOSBR or beam guidance, is a technique of directing a missile to its target by means of radar or a laser beam. The name refers to the way the missile flies down the guidance beam, which is aimed at the target. It is one of the simplest guidance systems and was widely used on early missile systems, however it had a number of disadvantages and is now found typically only in short-range roles.