A 14-week-old female West Highland White Terrier developed acute dyspnea. Radiographically there was an enlarged, hyperlucent caudal portion of the left cranial lung lobe and a diffuse, severe interstitial-to-alveolar pattern in the remaining lung lobes that was accentuated caudodorsally. Computed tomography confirmed the presence of the emphysematous lobe and further showed it to have focal lobar bronchial collapse. Lung lobe resection was performed, and the diagnosis was congenital lobar emphysema secondary to bronchial cartilage hypoplasia.