选择性缄默症（英语：Selective mutism）是一种社交焦虑症，患者有正常说话的能力，但在特定情境下就是说不出口。《精神疾病诊断与统计手册》把选择性缄默症描述为儿童的罕见心理失调。患有这症的儿童和成人能正常说话和理解语言，但在某些社交场合却无法说话。他们其他行为和学习能力都正常，尽管他们会不愿意参与团体活动。这就像是极端的害羞。但是症状的保持和程度，显然与害羞相异，譬如一个小孩在学校里完全静默，在家中却能自由说话，不过如有陌生人在场可能又令小孩静默。

选择性缄默症并不视为沟通障碍，因为大部份儿童患者会以面部表情和手势等沟通。有时候选择性缄默症是广泛性发展障碍或精神障碍的症状。

Selective mutism (SM) is an anxiety disorder in which a person who is normally capable of speech does not speak in specific situations or to specific people. Selective mutism usually co-exists with shyness or social anxiety. People with selective mutism stay silent even when the consequences of their silence include shame, social ostracism or even punishment.