Altruistic suicide is the sacrifice of one's life in order to save or benefit others, for the good of the group, or to preserve the traditions and honor of a society. It is always intentional. Benevolent suicide refers to the self-sacrifice of one's own life for the sake of the greater good. Such a sacrifice may be performed for the sake of executing a particular action, or for the sake of keeping a natural balance in the society.

Altruistic suicide was described by Émile Durkheim in his book Suicide: A Study In Sociology and occurs when social values and interests overwhelm the individual's interest in self-preservation. Altruistic suicide is one of four categories of suicide described by Durkheim, alongside egoistic suicide, fatalistic suicide, and anomic suicide.

In contrast, a "sacrifice" which is committed by the force of a state is referred to as eugenics or mass murder, but may be otherwise referred to as "enforced population limits" or "population control". In literature, examples may promote the concept as a means for ending enduring types of social conflict, or else deride the concept as an example of a dystopian future society.

Not all forms of suicide are viewed as a tragedy by the society in which they occur. Sociologists and anthropologists have observed that ritual suicide can be accepted or even expected in many cultures. For instance, the anthropologist Mary Douglas discusses a practice of the Dinka people in which divine leaders, known as Masters of the Fishing Spear, are buried alive in a ritual which allows their society to reconcile and even assert control over the inevitability of death.

An obligation to commit ritual suicide can also function to enforce certain cultural values or social roles. Japanese samurai practiced a form of ritual suicide called seppuku in which a warrior cuts open their own abdomen after experiencing martial disgrace. This practice may also serve the individual's own interests either by preserving the warrior's honor or preventing retribution by victorious opponents. Widows in India and Japan have committed acts of ritual suicide after the death of a husband, although these practices are now abandoned and often illegal. The Indian practice of widow suicide, called sati, typically occurs when the widow lies down or casts herself upon her husband’s funeral pyre in an act of ritual self-immolation. The elderly members of certain cultures intentionally ended their lives, in what is termed as senicide. In hunter-gatherer societies, death "was determined for the elderly ... normally characterized by a liminal period and ceremonies in which the old person was transferred from the present world to the next."

Durkheim also observes that altruistic suicide is unlikely to occur much in contemporary Western society where "individual personality is increasingly freed from the collective personality". Altruistic suicide has been described as an evolutionarily stable strategy. Altruistic suicide has a long history in India, even being noted in the Dharmashastras. Some perceive self-immolation as an altruistic or "worthy" suicide.

In contemporary Western society, this is seldom referred to as suicide, and most often referred to as an act of heroism. This only exists in times of emergency, and is always lauded, and is perceived as a tragic death.^{[citation needed]}

Self-sacrificial acts of heroism, such as falling on a grenade, is one example. Intentionally remaining on the deck of a sinking ship to leave room in the life rafts, intentionally ending one's life to preserve the resources of a group in the face of deprivation, and the like are suicidal acts of heroism. Firefighters, law-enforcement individuals, undercover agents, sailors, and soldiers more often are at risk of opportunities for this form of unplanned self-sacrifice. These are all a result of tragic, life-threatening emergencies. It is only an emergency measure, a voluntary but unwanted end to the person's life. It is never a result of long-term planned action, yet may involve some short-term planning. Examples of this include Vince Coleman, a telegraph operator who saved hundreds of lives by sending out a warning about an imminent explosion.