© 2014, WDG. All rights reserved. Optical coherence tomography (OCT) is a medical imaging modality that opens up new opportunities for imaging in breast cancer. It provides two- and three-dimensional micro-scale images of tissue structure from bulk tissue, in vivo or freshly excised without labeling or staining, is capable of video-rate acquisition speeds, and is compatible with compact imaging probes. In this paper, the authors briefly describe OCT technology and describe in detail its capabilities for imaging breast cancer. Potential applications identified in current research are discussed, particularly in the assessment of excised breast tumors. It is concluded that OCT shows promise for margin assessment and biopsy guidance but that much more research and validation is required to confirm its level of utility.