Many people use the words jealousy and envy interchangeably to describe the same emotional response, a general feeling of resentment towards a perceived rival. While the emotions of jealousy and envy do tend to overlap in some respects, there are some fundamental differences between the two. Jealousy, for example, is almost exclusively a negative emotion, while envy can has some positive effects, such as a renewed interest in self-improvement.

One difference between jealousy and envy involves the relationship between the jealous or envious person and his or her rival. An envious co-worker may develop a personal resentment towards a promoted co-worker because the position represents a higher salary and more responsibility. The true source of this envy is rarely the co-worker himself or herself, but the perceived value of the position. The co-worker may very well deserve the advancement because of his or her superior skills or education, but an envious person might become angry at himself or herself for not possessing those qualities.

Jealousy, on the other hand, focuses on the rival himself or herself, not necessarily the object or "good" at the center of the conflict. Jealousy implies a closer relationship between the jealous person and his or her rival. Instead of a promotion, the co-worker may start a romantic relationship with the jealous person's secret office crush. Because this rivalry is personal in nature, the target of the jealous person's resentment and anger is not necessarily the unattainable romantic partner, but the more attractive rival who now stands between them.

Another consideration between jealousy and envy is the depth of emotion. Envy is considered to be one of the 7 deadly sins, but in general the moral danger lies with becoming covetous of another person's possessions or status. In one sense, envy is at the root of criminal acts such as burglary or fraud. The criminal develops an irrational envy for people he or she perceives as more fortunate in life, so the theft of a victim's property somehow balances the scales of fairness. Envy in its rawest form represents an irrational desire for material satisfaction, not necessarily ill will towards those who have it.

Jealousy, however, is largely focused on the perceived character of the rival himself or herself. It's not that a more attractive rival managed to "steal" a potential romantic partner; it's the unfairness that an undeserving rival can use his or her skills to take what rightfully belongs to the jealous person. Feelings of jealousy often go deeper than feelings of envy, which can lead to physical confrontations with the rival or even criminal acts of violence.

Feelings of jealousy are almost always negative, since the jealous person may continue to build up resentment towards his or her rival until the situation becomes untenable or volatile. Many cases of jealousy can only be defused if at least one side of the triangle is taken completely out of the equation. If the object of the jealous person's romantic interest begins dating a third party, for example, the tension between rivals should lessen considerably. Without a focal point for passionate emotions, jealousy generally loses its fuel.

Envy, on the other hand, can actually have some positive benefits, albeit after the fact. An envious person may be motivated to take the steps necessary to attain what his or her rival already has. Instead of developing irrational feelings of resentment towards a successful co-worker, for example, an envious person might pursue the same educational track as his or her rival, or take other steps to improve his or her own chances for a similar promotion. Resolving feelings of envy does not necessitate the removal of a rival or the "good" he or she now possesses, but it could require an attitude adjustment on the part of the envious one.