A religious habit is a distinctive set of religious clothing worn by members of a religious order. Traditionally some plain garb recognizable as a religious habit has also been worn by those leading the religious eremitic and anchoritic life, although in their case without conformity to a particular uniform style.

Uniformity and distinctiveness by order often evolved and changed over time. Interpretation of terms for clothes in religious rules could change over centuries. Furthermore, every time new communities gained importance in a cultural area the need for visual separation increased for new as well as old communities. Thus, modern habits are rooted in historic forms, but do not necessarily resemble them in cut, colour, material, detail or use.

In Christian monastic orders of the Catholic, Lutheran and Anglican Churches, the habit often consists of a tunic covered by a scapular and cowl, with a hood for monks or friars and a veil for nuns; in apostolic orders it may be a distinctive form of cassock for men, or a distinctive habit and veil for women. Catholic Canon Law requires only that the garb of their members be in some way identifiable so that the person may serve as a witness of the Evangelical counsels.

In many orders, the conclusion of postulancy and the beginning of the novitiate is marked by a ceremony, in which the new novice is accepted as a novice and then clothed in the community's habit by the superior. In some cases the novice's habit will be somewhat different from the customary habit: for instance, in certain orders of women that use the veil, it is common for novices to wear a white veil while professed members wear black, or if the order generally wears white, the novice wears a grey veil. Among some Franciscan communities of men, novices wear a sort of overshirt over their tunic; Carthusian novices wear a black cloak over their white habit.