病态性嫉妒（又称嫉妒妄想或奥赛罗综合症），是妄想的一种，精神病的其中一种病征，常见于精神分裂症及妄想症的患者，临床上男性的发病率被女性高。患者会认为配偶或性伴侣不贞的妄想，患者藉琐细的佐证，例如房间衣橱内衣服的次序，就错误推论并且证实妄想为真，大部分情况下，这些指控完全是虚构，患者会尝试跟踪及骚扰怀疑的情敌，借此收集证据。但这种行为往往会伴随着激动情绪，甚至危险及攻击倾向。奥赛罗综合症的名称来自于莎士比亚笔下的角色奥赛罗。

Morbid jealousy, also known as Othello syndrome or delusional jealousy, is a psychological disorder in which a person is preoccupied with the thought that their spouse or sexual partner is being unfaithful without having any real proof, along with socially unacceptable or abnormal behaviour related to these thoughts. The most common cited forms of psychopathology in morbid jealousy are delusions and obsessions. It is considered a subtype of delusional disorder.