The main purposes of this thesis were to study the belief in Metteyya-Buddha in Therav̄āda Buddhism, beliefs in Metteyya-Buddha’s age as found in many textbooks, attitudes of Buddhist scholars and religious technocrats, and the expectation of result of belief in Metteyya-Buddha’s age of people in Roi-Et Municipality, Roi-Et Province.

The result of this study found that Metteyya was Bodhisatta coming to attain the Enlightenment and become the Buddha in this era. In the future, he had self-determination to be the Buddha when he was the king, Sangkhacakka Bodhisatta in the Sirimitta Buddha’s age. Later, he ordained in the Buddhist Order in the Sakyamuni; Buddha’s age and he was called Ajita Bhikkhu. He was foretold that he would become the Metteyya Buddha. The perfection made by the Metteyya Bodhisatta was ‘Buddhakaraka-dhamma’-elements to make a person the Buddha called ‘Dasaparami’ or ten perfections: giving, morality, renunciation, wisdom, effort, endurance, truthfulness, self-determination, loving kindness, and equanimity. In the last birth, he came to attain the perfection of giving in the middle of the Buddha’s age like Vessantara Bodhisatta, i.e. Sattasattaka-mahadāna, and giving children and a wife. More over, the Metteyya Bodhisata has 4 Buddhabhumikuna i.e. bravery to do good, wisdom, stability in
Adhitthāna and intent to do benefit for himself and others. The enlightenment of teachings that was not different from the Buddha in the past or the present was Four Noble Truths i.e. Dukkha (sufferring), Samudaya (cause of suffering), Niroda (cessation of suffering), and Magga (Eightfold Noble Path—path to the cessation of suffering). In the present time, Metteyya-Buddha was called Natha-devabutta Bodhisatta in the Tusita heaven. He was Niyata Bodhisatta predicted by the present Buddha that he would attain the enlightenment in the future. Here, Bodhisatta was meant a wise person who would attain the enlightenment, i.e. a person who practiced Fourfold Path to attain Bodhiñaṇa. Metteyya-Buddha was a Viriyadhika Bodhisatta that was the most extreme effort, i.e. great attempt and courage.

The beliefs in Metteyya-Buddha’s age as found in various textbooks of Thai Buddhists, attitude of Buddhist scholars and religious technocrats towards the Metteyya-Buddha’s age found that their beliefs due to faith that people completing three items of meritorious action including listening to thirteen episodes of the Buddha’s last great incarnation within one day would meet the Metteyya-Buddha. This was personal language called Puggalā-dhitthāna but in religious language it was called Dhammā-
dhi tthāna. When people loved, helped each other, and finally, lived harmoniously, the world would become immediately Metteyya-Buddha’s age. Such views on society in regards to philosophy and religion were also found in Plato’s Republic, Thomas More’s Utopia, Karl Marx’s communism.

The expectation of result of Metteyya-Buddha’s age of people in Roi-Et Municipality, Roi-Et Province was found that all believers had practiced frequently giving, morality, and meditation including the listening to the story of the Buddha’s last great incarnation. But one who was no belief in the Metteyya-Buddha’s age he/she did merit making for their happiness, Buddhists in each community came together to make the fulfillment of merit in organizing the tradition of the Buddha’s last great incarnation. They were harmonious, kind, helpful, and compassionate to each other. They derived all traditions including the story of the Buddha’s last great incarnation, generally called ‘Bunbhaved’ in E-san language that was an annual meritorious fulfillment of the Roi-Et province in March.  There were the painting and sculpture about the Buddha’s last great incarnation at many units of a temple such as the preaching hall, the Buddha’s hall, the sculpture of five Buddhas, and the painting of a Dhamma discourse between Phramalai and Metteyya Bodhisatta in the Tusita heaven in order to encourage people to make the fulfillment of merit if they wanted to appear in Metteyya Buddha’s age in the future.