Plain dress is a practice among some religious groups, primarily some Christian churches in which people dress in clothes of traditional modest design, sturdy fabric, and conservative cut. It is intended to show acceptance of traditional gender roles, modesty, and readiness to work and serve, and to preserve communal identity and separation from the immodest, ever-changing fashions of the world. For men, this often takes the form of trousers secured by suspenders, while for women, plain dress usually takes the form of a cape dress along with a headcovering (normatively a kapp or an opaque hanging veil).
Christian denominations that observe the wearing of plain dress, such as the Schwarzenau Brethren Anabaptists, do so because Jesus “condemned anxious thought for raiment” in and . They teach that the wearing of plain dress is scripturally commanded in , , and , in addition to being taught by the early Church Fathers:
In plain communities, women wear Christian headcoverings in keeping with the teaching of Saint Paul in , as well as that of the early Church Fathers.
The practice is generally found among the following Anabaptist branches: Amish (Old Order Amish, New Order Amish, Kauffman Amish Mennonites, Beachy Amish Mennonites), Para-Amish (Believers in Christ, Vernon Community, Caneyville Christian Community), Mennonites (Old Order Mennonites, Conservative Mennonites, traditional "Russian" Mennonites), Hutterites, the Bruderhof, Schwarzenau Brethren (Old Brethren, Old German Baptist Brethren, New Conference, Dunkard Brethren), and River Brethren (Old Order River Brethren and Calvary Holiness Church). Plain dress is also practiced by Conservative Friends and Holiness Friends (Quakers), in which it is part of their testimony of simplicity, as well as Old Regular Baptists, Plymouth Brethren, Cooperites and fundamentalist Mormon subgroups.
Among traditional Anabaptist groups, plain dress is an expression of their beliefs regarding modesty and veiling, as well as nonconformity to the world—which they see as consistent with the Bible and teachings of the early Church Fathers.