The That Luang Festival, also known as 'Boun That Luang', is a significant event that takes place annually in Vientiane, the capital city of Laos. Rooted deeply in the Buddhist tradition of the country, the festival is held at the That Luang Stupa, one of the most revered and respected monuments representing a symbol of both the Buddhist religion and the Lao sovereignty. The festival is mainly held in November, on the day of the full moon, and depends on the lunar calendar.

The That Luang Festival comprises a week-long series of religious rites and ceremonial events. The festival initiates with a pre-dawn gathering where hundreds and thousands of people engage in giving alms to hundreds of monks, a practice deeply integrated into the Lao culture. It continues with a grand procession in the late afternoon where people make vibrant offerings of fresh flowers, fruits, and candles at the shrine while reciting prayers. The festival usually ends with an enthralling fireworks display, making the atmosphere even more festive.

What makes That Luang Festival unique and appealing for locals and tourists alike is its cultural immersion. Traditional music and dance performances, along with the procession that veers through the main streets of the city dressed in colourful garb, truly depict the rich Lao culture. The occasional trade fair exhibiting various Lao goods and local culinary delicacies is also an integral part of the festival. It is a remarkable opportunity to experience the traditional social and religious practices of Laos and provides a deep insight into the country's heritage.