A domestic partnership is a relationship, usually between couples, who live together and share a common domestic life, but are not married (to each other or to anyone else). People in domestic partnerships receive legal benefits that guarantee right of survivorship, hospital visitation, and other rights.

The term is not used consistently, which results in some inter-jurisdictional confusion. Some jurisdictions, such as Australia, New Zealand, and the U.S. states of California, Maine, Nevada, Oregon and Washington use the term "domestic partnership" to mean what other jurisdictions call civil union, civil partnership, or registered partnership. Other jurisdictions use the term as it was originally coined, to mean an interpersonal status created by local municipal and county governments, which provides an extremely limited range of rights and responsibilities.

Some legislatures have voluntarily established domestic partnership relations by statute instead of being ordered to do so by a court. Although some jurisdictions have instituted domestic partnerships as a way to recognize same-sex marriage, statutes do exist which provide for recognition of opposite-sex domestic partnerships in many jurisdictions.

In some legal jurisdictions, domestic partners who live together for an extended period of time but are not legally entitled to common-law marriage may be entitled to legal protection in the form of a domestic partnership. Some domestic partners may enter into nonmarital relationship contracts in order to agree, either verbally or in writing, to issues involving property ownership, support obligations, and similar issues common to marriage. (See effects of marriage and palimony.) Beyond agreements, registration of relationships in domestic partnership registries allow for the jurisdiction to formally acknowledge domestic partnerships as valid relationships with limited rights.