油压马达（英语：Hydraulic motor)是一种将液压油的压力和流量转成扭力和角位移（转动）的机械致动器。油压马达相当于旋转的油压缸。观念上，油压马达应该可以转为油压泵，因为它们功能相反。就如同直流马达可以作为直流发电机。然而，多数的油压泵不可作为油压马达，因为它们不可反向驱动。而且，油压马达两端有特定的工作压力。

油压的泵、马达以及油压缸可组合成油压驱动系统。油压泵和油压马达组成油压变速器。

油压马达特性：相同的扭力输出时，体积较电动马达小。

A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation). The hydraulic motor is the rotary counterpart of the hydraulic cylinder.

Conceptually, a hydraulic motor should be interchangeable with a hydraulic pump because it performs the opposite function - similar to the way a DC electric motor is theoretically interchangeable with a DC electrical generator. However, most hydraulic pumps cannot be used as hydraulic motors because they cannot be backdriven. Also, a hydraulic motor is usually designed for working pressure at both sides of the motor.