Marriage is a socially and ritually recognized union between spouses that establishes rights and duties between them and their children, and between them and their in-laws, which are recognized interpersonal relationships, usually sexual. In the manual, marriage is recommended as a topic. When the race is defined, marriage is considered a cultural one.

Individuals can marry for a variety of reasons, including legal, social, sexual, emotional, financial, spiritual, and religious purposes. Who they marry can be influenced by socially determined rules of incest, prescriptive marriage rules, parental choice and individual desires. In some parts of the world, arranged marriages, child marriages, polygamy and sometimes forced marriages can be practiced as cultural traditions. Conversely, such practices can be banned and punished in parts of the world out of concern for women's rights and because of international law. In developed parts of the world, there has been a general tendency to ensure equal rights in marriage for women and to legally recognize the marriages of interfaith or interracial couples and same-sex couples. These trends coincide with the wider human rights movement.

Marriage can be recognized by a state, an organization, a religious authority, a tribal group, a local community, or peers. It is often seen as a contract. Civil marriage, which does not exist in some countries, is a marriage without religious content that is performed by a government agency in accordance with the marriage laws of the jurisdiction and is recognized to create the rights and obligations inherent in the marriage. Marriages can be performed in a secular civil ceremony or in a religious setting through a wedding ceremony. The marriage certificate usually creates normative or legal obligations between the persons involved and any offspring they produce. In terms of legal recognition, most sovereign states and other jurisdictions restrict marriage to opposite-sex couples and a decreasing number of these allow polygyny, child marriage, and forced marriage. Over the course of the twentieth century, a growing number of countries and other jurisdictions have lifted and legally recognized prohibitions on interracial marriage, interfaith marriage and, more recently, gender neutral marriage. Some cultures allow the dissolution of marriage by divorce or annulment. In some areas, child marriages and polygamy can occur, despite national laws prohibiting this practice.

Since the late twentieth century, major social changes in Western countries have led to changes in marriage demographics, with the age of first marriage increasing, fewer people getting married, and more couples choosing to live together rather than marry. . For example, the number of marriages in Europe fell by 30% between 1975 and 2005.