An Aerial Device or Elevating Work Platform is a mechanical device used to provide temporary access for people or equipment to inaccessible areas, usually at height.

They are generally used for temporary, flexible access purposes such as maintenance and construction work or by fire fighters for emergency access, which distinguishes them from permanent access equipment such as elevators. They are designed to lift limited weights (usually less than a ton, although some have a higher safe working load), distinguishing them from most types of cranes. They are usually capable of being fully operated (including set up) by a single person.

Regardless of the task they are used for, aerial work platforms may provide additional features beyond transport and access, including being equipped with electrical outlets or compressed air connectors for power tools. They may also be equipped with specialist equipment, such as carrying frames for window glass.

There are several distinct types of aerial work platforms, which all have specific features which make them more or less desirable for different applications. The key difference is in the drive mechanism that propels the working platform to the desired location. Most are powered by either hydraulics or possibly pneumatics. The different techniques also reflect in the pricing and availability of each type.

Aerial devices were once exclusively operated by hydraulic pistons, powered by diesel or gasoline motors on the base unit. Lightweight electrically powered units are gaining popularity for window-cleaning or other maintenance operations, especially indoors and in isolated courtyards, where heavier hydraulic equipment cannot be used. Aerial devices are the closest in appearance to a crane- consisting of a number of jointed sections, which can be controlled to extend the lift in a number of different directions, which can often include 'up and over' applications.

Work Platforms are fitted with safety or guardrails around the platform itself to contain operators and passengers. This is supplemented in most models by a restraining point, designed to secure a harness or fall arrestor. Some work platforms also have a lip around the floor of the platform itself to avoid tools or supplies being accidentally kicked off the platform. Some protocols require all equipment to be attached to the structure by its own lanyard.