Jealousy typically refers to the feelings, thoughts and behaviors that occur when a person believes that a valued relationship is being threatened by a rival. The word jealousy comes from the French jalousie, formed from jaloux. Feelings of jealousy always appear to stem from one's sense that something about their life is not secure e.g., in danger or is uncertain. Jealousy is the eruption of attachment and it can be transcended only through awareness. As we move with awareness into the center of this phenomenon, we pass through ungrounded expectations and beliefs, projections and delusions, guilt, envy, the loss of self-esteem, and the threat to security. The core is an existential problem and it has to do with illusion and the effectively fearful nature of the ego. When we come to know and accept the nothingness at the core, jealousy and the pain of fanatical attachment cease.

Jealousy is a common experience in human relationships and it has been reported in every culture and in many forms where researchers have looked .It has been observed in infants as young as 5 to 6 months old and in adults over 65 years old. The complexity of jealousy allows people to describe it in different ways. Definitions of jealousy normally share basic themes. These shared themes indicate jealousy is a meaningful concept and it can also be distinguished from concepts such as envy. In simple terms, jealousy is a feeling of protective resentment towards one who threatens a value or relationship.

People who have experienced pathological jealousy and for whom jealousy triggers violence may advantage from professional counseling. People who experience usual jealousy have at least nine strategies for coping with jealousy. The problem-solving strategies include: improving the primary relationship, interfering with the rival relationship, self-assessment and demanding commitment. The emotion-focused strategies include: derogation of partner or rival, denial/avoidance, developing alternatives, support/catharsis, and appraisal challenge. These strategies are related to emotion regulation, cognitive change, conflict management, and ground rules for managing jealous competition. The most important thing to do about any feelings of jealousy is to first confess them, and then attempt to overcome them.

While mainstream psychology considers sexual arousal through jealousy a paraphilia (categorized as zelophilia), some authors on sexuality (Serge Kreutz, Instrumental Jealousy) have argued that jealousy in manageable dimensions can have a definite positive effect on sexual satisfaction and sexual function. Jealousy sometimes heightens passion towards partners and increases the strength of passionate sex. Jealousy varies across cultures, cultural learning can manipulate the situations that trigger jealousy and the manner in which jealousy is expressed and attitudes toward jealousy can also change within a culture over time. Jealousy is the powerful complex of emotions experienced at the loss, real or imagined, of someone or something you believe is yours, whereas envy concerns what you do not have and would like to possess Jealousy in religion examines how the scriptures and teachings of different religions deal with the topic of jealousy. Religions may be compared and contrasted on how they deal with two issues: rules and concepts of divine jealousy about the aggravation and expression of human jealousy.