Dowsing is a type of divination employed in attempts to locate ground water, buried metals or ores, gemstones, oil, claimed radiations (radiesthesia), gravesites, malign "earth vibrations" and many other objects and materials without the use of a scientific apparatus. It is also known as divining (especially in water divining), doodlebugging (particularly in the United States, in searching for petroleum or treasure) or (when searching for water) water finding, or water witching (in the United States).

A Y-shaped twig or rod, or two L-shaped ones—individually called a dowsing rod, divining rod (Latin: virgula divina or baculus divinatorius), vining rod, or witching rod—are sometimes used during dowsing, although some dowsers use other equipment or no equipment at all. The motion of such dowsing devices is generally attributed to the ideomotor phenomenon, a psychological response where a subject makes motions unconsciously. Put simply, dowsing rods respond to the user's accidental or involuntary movements.

The scientific evidence shows that dowsing is no more effective than random chance. It is therefore regarded as a pseudoscience.