The Jet d'Eau (French pronunciation: [ʒɛ do], Water-Jet) is a large fountain in Geneva, Switzerland, and is one of the city's most famous landmarks, being featured on the city's official tourism web site and on the official logo for Geneva's hosting of the 2008 UEFA Championships. Situated at the point where Lake Geneva empties into the Rhône, it is visible throughout the city and from the air, even when flying over Geneva at an altitude of 10 kilometres (33,000 ft).

Five hundred litres (110 imp gal; 130 US gal) of water per second are jetted to an altitude of 140 metres (460 ft) by two 500 kW pumps, operating at 2,400 V, consuming one megawatt of electricity. The water leaves the nozzle at a speed of 200 kilometres per hour (120 mph). Diameter of the nozzle is exactly 4 inches (10 cm). Maximum height of water jet is about 140 metres (460 ft) above water level. When it is in operation, at any given moment there are about 7,000 litres (1,500 imp gal; 1,800 US gal) of water in the air. Unsuspecting visitors to the fountain—which can be reached via a stone jetty from the left bank of the lake—may be surprised to find themselves drenched after a slight change in wind direction.