In Christianity (especially in the Roman Catholic, Orthodox, Anglican and Methodist traditions), an oblate is a person who is specifically dedicated to God and to God's service.

Oblates are individuals, either laypersons or clergy, normally living in general society, who, while not professed monks or nuns, have individually affiliated themselves with a monastic community of their choice. They make a formal, private promise (annually renewable or for life, depending on the monastery with which they are affiliated) to follow the Rule of the Order in their private lives as closely as their individual circumstances and prior commitments permit. Such oblates are considered an extended part of the monastic community; for example, Benedictine oblates also often include the post-nominal letters 'OblSB' or 'ObSB' after their names on documents. They are comparable to the tertiaries associated with the various mendicant orders.

The term "oblate" is also used in the official name of some religious institutes as an indication of their sense of dedication

Many Benedictine communities still retain secular oblates. These are either clergy or laypeople affiliated in prayer with an individual monastery of their choice, who have made a formal private promise (annually renewable or for life) to follow the Rule of St. Benedict in their private life at home and at work as closely as their individual circumstances and prior commitments permit.

In the Roman Catholic Church, the oblate is in an individual relationship with the monastic community and does not form a distinct unit within the Church,  and there are no regulations in the modern canon law of the Church regarding them. One consequence is that non-Catholic Christians can be received as oblates of a Catholic monastery. Similarly, in Methodist monasteries, non-Methodist Christians can be received as oblates. The same is the case with many Anglican monasteries, which accept non-Anglican Christians as oblates.

Third Order

The term third order signifies, in general, lay members of Christian religious orders, who do not necessarily live in a religious community such as a monastery or a nunnery, and yet can claim to wear the religious habit and participate in the good works of a great order. Roman Catholicism, Lutheranism and Anglicanism all recognize third orders.

Third orders were a 12th-century adaptation of the medieval monastic confraternities. Members of third orders are known as tertiaries (Latin tertiarii, from tertius, "third"). In some cases, they may belong to a religious institute (a "congregation") that is called a "third-order regular".

Roman Catholic canon law states:

"Associations whose members share in the spirit of some religious institute while in secular life, lead an apostolic life, and strive for Christian perfection under the higher direction of the same institute are called third orders or some other appropriate name."