Āsāḷha Pūjā[2] (Thai: อาสาฬหบูชา) is a Theravada Buddhist festival which typically takes place in July,[3] on the full moon of the Āsādha month.

It is celebrated in Indonesia, Cambodia (Khmer: ពិធីបុណ្យអាសាឡ្ហបូជា), Thailand, Sri Lanka, Laos, Myanmar and in other countries with Theravada Buddhist populations.

Asalha Puja, also known as Dharma Day, is one of Theravada Buddhism's most important festivals, celebrating as it does the Buddha's first sermon, the Sermon in the Deer Park at Sarnath,[4] in which he set out to his five former associates the doctrine that had come to him following his enlightenment.

This first sermon is not only the first structured discourse given by the Buddha after his enlightenment, it also contains the essence of all his subsequent teaching.

At the end of the talk, one of the five participants recounted his understanding of what had been said and asked to be received as a disciple, a request the Buddha granted, thus establishing the first order of monks.