Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal form of fibrotic lung disease, with a 3 year survival rate of 50%. Diagnostic certainty of IPF is essential to determine the most effective therapy for patients, but often requires surgery to resect lung tissue and look for microscopic honeycombing not seen on chest computed tomography (CT). Unfortunately, surgical lung resection has high risks of associated morbidity and mortality in this patient population. We aim to determine whether bronchoscopic optical coherence tomography (OCT) can serve as a novel, low-risk paradigm for in vivo IPF diagnosis without surgery or tissue removal. OCT provides rapid 3D visualization of large tissue volumes with microscopic resolutions well beyond the capabilities of CT. We have designed bronchoscopic OCT catheters to effectively and safely access the peripheral lung, and conducted in vivo peripheral lung imaging in patients, including those with pulmonary fibrosis. We utilized these OCT catheters to perform bronchoscopic imaging in lung tissue from patients with pulmonary fibrosis to determine if bronchoscopic OCT could successfully visualize features of IPF through the peripheral airways. OCT was able to visualize characteristic features of IPF through the airway, including microscopic honeycombing (< 1 mm diameter) not visible by CT, dense peripheral fibrosis, and spatial disease heterogeneity. These findings support the potential of bronchoscopic OCT as a minimally-invasive method for in vivo IPF diagnosis. However, future clinical studies are needed to validate these findings.