Objective: To highlight the case of a patient with acute respiratory failure, whose diagnosis of Boerhaave’s syndrome only became apparent after a trial of non-invasive ventilation. Clinical Presentation and Intervention: A 68-year-old female presented with a clinical picture of community-acquired pneumonia and exacerbation of asthma that was supported by radiological evidence of a large left-sided pleural effusion. Within 20 h, she deteriorated and progressed to severe type 2 respiratory failure. After initiation of first non-invasive and then invasive ventilation, a tension pneumothorax developed. An emergency decompression of the chest revealed gastric contents in the left hemithorax. A diagnosis of Boerhaave’s syndrome was made. Subsequent management included a thoracotomy, defunctioning oesophagectomy, and gastrostomy with ventilatory and inotropic support. However, despite best efforts, the severe systemic inflammatory response resulted in death 3 weeks after initial presentation. Conclusion: It is important to have an open diagnostic mind with a thorough review of investigations and therapy as a patient deteriorates. This case illustrates the importance of considering the remote possibility of oesophageal rupture prior to commencing non-invasive ventilation, especially with regard to chest radiograph features.