The Somawathiya Chaitya (Sinhala: සෝමාවතිය චෛත්‍ය, Tamil: சோமாவதிய சைத்யா)[2] is a Buddhist Stupa situated in the ancient city of Polonnaruwa, Sri Lanka.

[3][4] The Somawathiya Chaitya[5] is located within the Somawathiya National Park[6] on the left bank of the Mahaweli River,[7] and is believed to have been built long before the time of Dutugamunu enshrining the right canine Relic of the tooth of the Buddha.

It is attributed to the reign of King Kavan Tissa - Dutugemunu's father - who ruled Magama.

The stupa is named after Princess Somawathi, the sister of King Kavantissa, and the wife of regional ruler Prince Giri Abhaya.

Upon completion of the stupa and other constructions, the prince and princess handed over the temple to Arahat Mahinda and other monks.