A promise ring or friendship ring is a small, inexpensive ring given to a boyfriend or girlfriend, to promise not to court a rival. These indicate merely that serious courting is under way. No permanent commitment has been made by either party, but they give the partners an excuse for refusing social invitations from others.

In American society, a subculture in adolescent behavior exists. High school class rings (rings purchased to represent one's high school and year of graduation) are coveted by young women. "Wearing his class ring" means that the couple is 'going steady' and that theirs is an exclusive relationship (if the young man wears a 'letter jacket ' -- an overt symbol of athletic participation -- the young lady may be gifted with that to show she's 'taken').

Some girls judge the seriousness of a promise ring by its value and by the size of its gem. In general, promise rings with a value of more than a half-week's pay might be considered engagement rings and are refused if the woman lacks a desire for a permanent relationship with the man.

In some cultures, young adults in partnership wear 'friendship rings' as a sign of their commitment to each other. Generally speaking, however, 'promise rings' are uncommon except for the very young.