Marriageable age (or marriage age) is the general age, as a legal age or as the minimum age subject to parental, religious or other forms of social approval, at which a person is legitimately allowed for marriage. Age and other prerequisites to marriage vary between jurisdictions, but in the vast majority of jurisdictions, the marriage age as a right is set at the age of majority. Nevertheless, most jurisdictions allow marriage at a younger age with parental or judicial approval, and some also allow adolescents to marry if the female is pregnant. The age of marriage is most commonly 18 years old, but there are variations, some higher and some lower. The marriageable age should not be confused with the age of majority or the age of consent, though they may be the same in many places.

The 55 parties to the 1962 Convention on Consent to Marriage, Minimum Age for Marriage, and Registration of Marriages have agreed to specify a minimum marriage age by statute law‚ to override customary, religious, and tribal laws and traditions. When the marriageable age under a law of a religious community is lower than that under the law of the land, the state law prevails. However, some religious communities do not accept the supremacy of state law in this respect, which may lead to child marriage or forced marriage. The 123 parties to the 1956 Supplementary Convention on the Abolition of Slavery have agreed to adopt a prescribed "suitable" minimum age for marriage. In many developing countries, the official age prescriptions stand as mere guidelines. UNICEF, the United Nations children's organization, regards a marriage of a minor (legal child), a person below the adult age, as child marriage and a violation of rights.

Until recently, the minimum marriageable age for females was lower in many jurisdictions than for males, on the premise that females mature at an earlier age than males. This law has been viewed by some to be discriminatory, so that in many countries the marriageable age of females has been raised to equal that of males.