he Vietnamese Eucharistic Youth society (Thiếu Nhi Thánh Thể abbreviated tntt in Vietnamese) is a non-profit organisation under the leadership of the Catholic church. Its aim is to develop  the physical, mental and spiritual well-being of Vietnamese Catholic youth so that may become healthy adults as well as better Christians.

The Eucharistic Youth society was founded in Europe during World War I and was known as the Eucharistic Crusade. Its purpose at the time was to pray, especially to the Blessed Sacrament, for the conversion of hearts and the reconciliation among the disillusioned youths affected by the War. Although the Eucharistic Crusade was founded by a Jesuit, Pere Bessiere, S.J., it was brought to Hanoi, Viet-Nam, by Sulpicians in 1929. By 1951, it had spread throughout the whole country and became an organised association in the early 1960's.

In 1964, in keeping with the spirit of the second Vatican Council, the Vietnamese Eucharistic Crusade was transformed into the Vietnamese Eucharistic Youth Society and was approved by the National Conference of Catholic Bishops and the government. This new transition integrated both prayer and apostolate services. From 1964 to 1975, the Society grew considerably in in spirit and in number. In order to accommodate the growth of the society, the first National Convention, "Promised Land I", was held in 1972. Over 2,000 co-ordinating leaders attended. By 1975, there were about 140,000 members, under the leadership of about 3,800 co-ordinating leaders serving in 650 parishes within 13 dioceses in South Viet-Nam alone.

With the fall of South Viet-Nam in 1975, the society's activities ceased temporarily. However, with the waves of refugees fleeing to new homeland, the Society came to life again. The Vietnamese Eucharistic Youth Society is currently active in many different countries in the free world: Australia, Canada, Europe, Japan and the United States.

The Society was formed in Australia in 1984.