Vesak, also known as the birthday of the historical Buddha or Shakyamuni Buddha, commemorates the birth of Prince Siddhartha, who later became the Buddha, around the end of the fourth century B.C. This occasion holds deep significance for Buddhists worldwide, though the date of celebration varies depending on the particular school of Buddhism or the country's traditions.

Siddhartha was born in Lumbini, which is at the border of what is India and Nepal today. His mother, Maya, was the wife of Suddhodana, king of the Shakya clan. According to Buddhist lore, the queen dreamed that an auspicious white elephant entered her womb when she conceived. A number of texts recount the child’s miraculous birth, detailing how the baby was received by the gods Indra and Brahma, and how he took seven steps soon after he was born. He is then believed to have received a cleansing bath from the gods or dragon kings, depending on the country or culture where the legend originated.

Suddhodana sheltered his son from pain and suffering, believing that keeping him isolated would lead him to become king. However, he could not protect Siddhartha for long, and the prince began to reflect after witnessing sickness, old age and death. Disillusioned by the impermanence of life, Siddhartha engaged in six years of ascetic practice and attained enlightenment at age 35 in Bodh Gaya in northeast India. He then became known as the Buddha, which means "the awakened one."

Buddhists around the world use this time not only to celebrate but also to reflect on Buddha’s teachings and what it means to practice the faith. In many parts of Asia, the sacred day marks not just the birth but also the enlightenment and passing of the Buddha. In most Asian cultures and the diaspora, Buddhists go to their local temples and participate in chanting, meditation and festivities all day. Families decorate their homes with lanterns and gather for feasts.

Buddha’s birthday is a national holiday in South Korea. The highlight of the celebration in Seoul is the lotus lantern festival called Yeondeunghoe, a parade of thousands of colorful, lighted paper lanterns often shaped like lotus flowers that are hung in temples and streets. On Buddha’s birthday, many temples provide free meals and tea to all visitors. Festivities in temple yards and parks include traditional games and various performing arts displays. The luminous display is believed to symbolize the light of Buddha’s teachings.

While Buddha’s birthday is not an official holiday in North Korea, it has been observed in Buddhist temples there since 1988. In 2018, Buddhist monks in North and South Korea held joint services when animosities between their governments eased. But such exchange programs have been stalled in the past few years due to tensions over North Korea’s nuclear program.

In China, the faithful perform a bathing ceremony that involves pouring scented blessedatue of the infant Buddha whose right forefinger points upwards toward the sky and left forefinger points water over a st down to the Earth. According to legend, the Buddha announced shortly after being born that he would have no more rebirths, and the dragons of heaven baptized him with pure water.

In Japan, April 8 is observed as Buddha’s birthday and is celebrated in Buddhist temples as Hana Matsuri, which means flower festival. On this day, a small "flower hall" is set up on temple grounds and decorated with colorful flowers. A bowl of water with a statue of the baby Buddha is placed in the middle, and devotees pour sweet tea on the statue's head. A priest performs the Kambutsu-e nativity festival, recreating Buddha’s birth in the garden of Lumbini.

Countries in South and Southeast Asia celebrate Buddha’s birthday on the full moon of the second lunar month, known as Vesakha or Vaisakha. The Sanskrit word for full moon is Purnima, which is why the holiday is also called Buddha Purnima. The Mahabodhi Temple in Bodh Gaya is decorated on this day and devotees perform special prayers under the bodhi tree under which the Buddha is believed to have attained enlightenment. In India and Nepal, sweet rice porridge is served on this day to recall the story of Sujata, a maiden who offered the Buddha a bowl of milk porridge.

In Malaysia and China, caged animals and birds are set free on Buddha’s birthday because people believe it is good karma. In Sri Lanka, celebrants decorate homes and streets with candles, paper and bamboo lanterns. Festivities feature devotional songs, decorative structures called "pandals," burning of incense, and electric light displays that depict stories from Buddha’s life. In South Vietnam, Buddha’s birthday is a popular festival but not a public holiday. It was held from 1958 to 1975.