A marriage of convenience is a marriage contracted for reasons other than the traditional reasons of love or family, that is, with a particular end in mind.

Marriages of convenience are contracted, for example, for reasons of citizenship or right of abode or, in situations where homosexuality is punishable or potentially detrimental, to create the appearance of heterosexuality. Such marriages may have one heterosexual and one homosexual partner, or two homosexual partners. In the case where a gay man marries a woman, the woman is said to be his "beard." Both Oscar Wilde and Cole Porter are said to have had marriages of convenience to hide their homosexuality. See also Lavender marriage.

In more recent times, the "marriage of convenience" has been used to mean any partnership between groups or individuals for their mutual (and sometimes illegitimate) benefit, or between groups or individuals otherwise unsuited to working together. An example would be a "National Unity Government", as existed in Israel during much of the 1970s or in Second World War Australia. Another example on a smaller scale would be the effective coalition between the Liberal Party of Australia's Campbell Newman and the Australian Labor Party - dominated Brisbane City Council .

Such partnerships are often referred to jokingly as a "marriage of inconvenience", particularly where real co-operation between the parties is absent.

The phrase is a calque of French mariage de convenance - a marriage of convention, or marriage of suitability.