Vat That Khao, also known as Wat That Khao, is a serene Buddhist temple in Vientiane, Laos, located across from the Royal Park and Don Chan Palace on Fa Ngum Quay. It lies near prominent landmarks such as Vat Phiavat, Vat Si Meuang, and the King Sisavang Vong Monument. Most notably, it is nestled beside the revered Vat That Luang, Laos’ most sacred site, which houses a relic believed to be Buddha’s breastbone, dating back to 300 BC.