A stupa (from Sanskrit: m., स्तूप, stūpa, Sinhalese: ස්ථූපය, Pāli: थुप "thūpa", literally meaning "heap") is a mound-like structure containing Buddhist relics, typically the remains of Buddha, used by Buddhists as a place of worship. After "stupa", "chorten" is the most commonly encountered English term. The term "reliquary" is sometimes used, after a Christian functional equivalent. Stupas are an ancient form of mandala.

The stupa is the oldest Buddhist religious monument and was originally only a simple mound of mud or clay to cover relics of the Buddha (cetiya). After the parinirvana of the Buddha, his remains were cremated and the ashes divided and buried under eight stupas with two further stupas encasing the urn and the embers. Little is known about these early stupas, particularly since it has not been possible to identify the original ten monuments. However, some later stupas, such as at Sarnath and Sanchi, seem to be embellishments of earlier mounds.