An honor killing, or honour killing (also: honor murder) is the homicide of a member of a family or social group by other members, due to the belief of the perpetrators that the victim has brought dishonor upon the family or community. Honor killings are directed mostly against women and girls, but have been extended to men.

The perceived dishonor is normally the result of one of the following behaviors, or the suspicion of such behaviors: dressing in a manner unacceptable to the family or community, wanting to terminate or prevent an arranged marriage or desiring to marry by own choice, especially if to a member of a social group deemed inappropriate, engaging in heterosexual acts outside marriage and engaging in homosexual acts.

Many women's groups in the Middle East and Southwest Asia suspect that more than 20,000 women are killed each year.

Human Rights Watch defines "honor killings" as follows:

Honor killings are acts of vengeance, usually death, committed by male family members against female family members, who are held to have brought dishonor upon the family. A woman can be targeted by (individuals within) her family for a variety of reasons, including: refusing to enter into an arranged marriage, being the victim of a sexual assault, seeking a divorce—even from an abusive husband—or (allegedly) committing adultery. The mere perception that a woman has behaved in a way that "dishonors" her family is sufficient to trigger an attack on her life.