闭塞性细支气管炎（英语：bronchiolitis obliterans，缩写为BO），又名缩窄性细支气管炎，是一种罕见、致命且不可逆的阻塞性肺病。该病表现为因炎症或纤维化所导致的细支气管狭窄或阻塞。有时闭塞性细支气管炎也被用于特指一种腺病毒导致的小儿细支气管炎严重亚型。闭塞性细支气管炎也被认为是移植排斥慢性期的肺部表现。

病名中“细支气管炎”是指细支气管的炎症性反应，而“闭塞性”是指由于炎症反应及纤维化所导致的细支气管部分或完全性的阻塞

Bronchiolitis obliterans (BO), also called obliterative bronchiolitis (OB) and constrictive bronchiolitis (CB), is a rare and life-threatening form of non-reversible obstructive lung disease in which the bronchioles (small airway branches) are compressed and narrowed by fibrosis (scar tissue) and/or inflammation. Bronchiolitis obliterans is also sometimes used to refer to a particularly severe form of pediatric bronchiolitis caused by adenovirus.