A mutual organization, or mutual society is an organization (which is often, but not always, a company or business) based on the principle of mutuality and governed by private law. Unlike a true cooperative, members usually do not contribute to the capital of the company by direct investment, but derive their right to profits and votes through their customer relationship. A mutual organization or society is often simply referred to as a mutual.

A mutual exists with the purpose of raising funds from its membership or customers (collectively called its members), which can then be used to provide common services to all members of the organization or society. A mutual is therefore owned by, and run for the benefit of, its members – it has no external shareholders to pay in the form of dividends, and as such does not usually seek to maximize and make large profits or capital gains. Mutuals exist for the members to benefit from the services they provide and often do not pay income tax.

Surplus revenue made will usually be re-invested in the mutual for the benefit of the members and for internal financing, to sustain or grow the organization, and to make sure it remains safe and secure.