Polygamy is the practice or state of being married to more than one spouse at the same time, often called “plural marriage.”

Quick definition

  • In everyday and legal use, polygamy means one person having multiple legal or culturally recognized spouses at once.
  • It contrasts with monogamy , where someone has only one spouse at a time.

Main types of polygamy

Experts usually break polygamy down into a few main forms:

  1. Polygyny
    • One man is married to more than one woman at the same time.
 * This is historically the most common form worldwide.
  1. Polyandry
    • One woman is married to more than one man at the same time.
 * Much rarer and usually tied to very specific cultural or economic conditions (for example, limited land or resources).
  1. Group marriage
    • Several men and several women are all married to one another in a shared marital unit.

Some scholars also talk about “social” or “sexual” polygamy more broadly, meaning people having multiple long‑term or sexual partners, not always legally married.

Legal and cultural context

  • In many Western countries (like the United States), polygamous marriage is illegal; entering a second marriage while still married can be prosecuted as bigamy.
  • In some regions of the Middle East, Africa, and parts of Asia, certain forms of polygyny are legally or religiously permitted and socially recognized.
  • Around the world today, polygamy is often debated in relation to human rights, gender equality, religious freedom, and social stability.

How it differs from related ideas

  • Polyamory : multiple intimate or romantic relationships with the knowledge and consent of everyone involved, but not necessarily involving marriage.
  • Open relationships/ethical non‑monogamy : umbrella terms for relationships where partners agree that more than two people can be involved romantically or sexually, again often without legal marriage.

In short, when people ask “what is polygamy,” they’re usually talking about a marital system where someone has more than one spouse at the same time, recognized by law, religion, or culture, with different forms and legal status depending on where and how it’s practiced.