扰流板（英语：Spoiler）又称减速板，为使用涡轮喷气发动机和涡轮风扇发动机的固定翼航空器（包括喷气式飞机和滑翔机）上常用的一种减速装置。因为其结构简单，可靠性高，从小型到大型飞机上的应用相当广泛。民用客机的扰流板通常安装在两侧的机翼上，使用时通过液压系统顶起，有效地增加航空器前进的阻力并增大机翼上方的压力，达到同时减缓飞行速度和降低飞行高度的目的。相对的，战斗机上的扰流板根据各自空气动力设计的不同，安装在不同的位置。另外，不少战斗机降落时需要靠释放减速伞来缩短滑跑的距离。但是减速板的使用寿命有限，一般来讲只能使用1000-3000个小时。

In aeronautics, a spoiler (sometimes called a lift spoiler or lift dumper) is a device intended to intentionally reduce the lift component of an airfoil in a controlled way. Most often, spoilers are plates on the top surface of a wing that can be extended upward into the airflow to spoil it. By so doing, the spoiler creates a controlled stall over the portion of the wing behind it, greatly reducing the lift of that wing section. Spoilers differ from airbrakes in that airbrakes are designed to increase drag without affecting lift, while spoilers reduce lift as well as increasing drag.