In the Anabaptist tradition, an Ordnung is a set of rules describing the way of life of church members. The term is mostly used by Amish and Old Order Mennonites. Ordnung (pronounced [ˈɔʁdnʊŋ] ^ⓘ) is the German word for order, discipline, rule, arrangement, organization, or system. Because the Amish have no central church government, each assembly is autonomous and is its own governing authority. Thus, every local church maintains an individual set of rules, adhering to its own Ordnung, which may vary from district to district as each community administers its own guidelines. Among the Amish, these rules are largely unwritten, yet they define the very essence of Amish identity. Conservative Mennonites refer to Ordnung by the English terms "discipline" or "standard", and their rules are usually written.

Anabaptists, such as the Amish, believe in a literal interpretation of the Bible. Thus the Ordnung is intended to ensure that church members live according to the biblical Word of God, as they understand it. The Ordnung is a set of behavioral rules, and all members within a church agree to have their lives ordered by that code. Each person is expected to live simple lives devoted to God, to family, and to the community, based upon their understanding of God's laws.

To the Amish, the Ordnung provides a strong sense of group identity. Ultimately, adherents claim that its rules are supported by scripture, and they believe that persecution is the natural result of Christian discipleship. The Ordnung creates boundaries for the Amish, and they view it much like a children's schoolyard fence – remaining within the enclosure allows them freedom, but to cross the fence would mean worldly danger.^{[page needed]}

In Garry Schmidt's book, Early Anabaptist Spirituality, he argues that a person who has learned to live within a respectful Ordnung appreciates the value of freedom of heart, peace of mind, and clear conscience. And he indicates that such a person had more freedom, more liberty, and more privilege than those outside the church.

Some of the most common Ordnung rules are: separation from the world, hard work, a woman's submission to her husband, mode of dress, and refusal to buy insurance. Non-Amish often think of the Ordnung in terms of restrictions (e.g., women must submit to husbands, no electrical power lines, no telephone in the home, no personal ownership of automobiles). However, many of the Ordnung guidelines also focus on cultivating what the Amish see as beneficial character traits. The Ordnung attempts to prevent pride, envy, vanity, laziness, dishonesty, etc.

According to the Amish, the purpose of the Ordnung is to guide Amish behavior into being more Christ-like, thus defining who they are. It ultimately intends that they be separate and different from the world. As such, anything viewed as disruptive to their society, such as personal power, wealth, and status, are funneled through the Ordnung social order. Disobedience to these lifestyle regulations is punished by discipline initiated by the church leaders. One of the more severe actions that the Amish bishop can mete out is Shunning (Meidung).

An Amish minister says of the Ordnung: A respected Ordnung generates peace, love, contentment, equality, and unity. It creates a desire for togetherness and fellowship. It binds marriages, it strengthens family ties to live together, to work together, to worship together and to commune secluded from the world.

— Donald B. Kraybill, The Riddle of Amish Culture, p. 98