A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level.

In automatic control terminology, a control valve is termed a "final control element".


A control valve consists of three main parts in which each part exist in several types and designs:

- Valve’s actuator type
- Valve’s positioner type
- Valve’s body material