A glider or sailplane is a type of glider aircraft used in the sport of gliding. They have rigid wings and an undercarriage. Some gliders, known as motor gliders are also used for gliding and soaring, but have engines which can be used for extending a flight and, for some types, for take-off. Aircraft such as hang gliders and paragliders are foot-launched and so are described in separate articles, though their differences from sailplanes are covered below. Glider aircraft that are used for purposes other than recreation, for example for military purposes, do not soar.

Sports gliders benefit from creating the least drag for any given amount of lift, and this is best achieved with long, thin wings and a fully faired narrow cockpit. Aircraft with these features are able to climb efficiently in rising air and can glide long distances at high speed with a minimum loss of height in between.

Although most gliders do not have engines, there are a few that do. (see Motor glider). The manufacturers of high-performance gliders will list an optional engine with a retractable propeller that can be used to sustain flight, if required; these are known as 'self-sustaining' gliders. Some have enough thrust to launch themselves before the engine is retracted and are known as 'self-launching' gliders. There are also 'touring motor gliders' which can self launch and switch off the engine in flight without retracting their propellers.

Glider may refer to: