An engagement ring is a ring indicating that the person wearing it is engaged to be married, especially in Western cultures. A ring is presented as an engagement gift by a partner to their prospective spouse when they propose marriage or directly after a marriage proposal is accepted. It represents a formal agreement to future marriage. In Western countries, engagement rings are worn mostly by women, and rings can feature diamonds or other gemstones. The neologism "mangagement ring" is sometimes used for an engagement ring worn by men. In some cultures, men and women wear matching rings, and engagement rings may also be used as wedding rings. In the Anglosphere, the ring is customarily worn on the left hand ring finger, but customs vary considerably elsewhere across the world.

Historically, engagement rings are blessed and then worn during the betrothal ceremony of a couple, but neither the engagement nor any other ring is worn during the wedding ceremony, when the wedding ring is put by the groom on the finger of the bride as part of the ceremony, and sometimes by the bride onto the groom's finger. After the wedding, the engagement ring is usually put back on and is usually worn on the outside of the wedding ring.