Bak Full Moon Poya Day is a significant holiday in Sri Lanka that takes place during the month of April. This public holiday is celebrated on the full moon day of Bak, which is the second month of the Sinhalese calendar. This day holds great religious significance to the Buddhists of Sri Lanka. The entire day is dedicated to meditating and observing Sil - the eight precepts of Buddhism.

The Bak Full Moon Poya Day is of immense importance as it marks two noteworthy events in Buddhist history. First, it marks the second visit of Gautama Buddha to Sri Lanka. This visit was to settle a dispute between two Naga Kings - Chulodara and Mahodara, who were quarrelling over the throne at a place called Maniakkhika. Secondly, on this day, Buddha is said to have concluded his sermon on the practice of discipline - Vinaya.

On Bak Full Moon Poya Day, devotees flock to temples all over the country to make merit by engaging in religious activities such as meditation, chanting and listening to sermons. The streets of the country are blanketed in quiet peace as all liquor shops, meat shops and betting centres remain closed. The whole atmosphere resonates with calm and peace, and every corner of Sri Lanka becomes a judiciary of Buddhist philosophy.