The ASH 25 is a two-seater high performance Open Class glider manufactured by Alexander Schleicher from 1986 until September 2008, originally with a 25-metre wingspan. It was superseded in production by the ASH 30.

A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding. This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplanes are aerodynamically streamlined and so can fly a significant distance forward for a small decrease in altitude.