Coronary artery bifurcation lesions pose major challenges despite significant advancements in stent technology and development of specific bifurcation stenting approaches. Optical coherence tomography (OCT) is an intracoronary imaging technique with the highest resolution and can generate automatically contoured lumen areas across the variable geometry of bifurcation lesions. Knowledge of plaque severity and composition enables planning of the best strategy for percutaneous coronary intervention (PCI) and stenting. The provisional stent strategy can be modified when there is high risk of side-branch compromise at the ostium after main vessel stenting. OCT allows the identification of the site of guide wire crossing, an important determinant of the final result. OCT can also assist in the assessment of the procedural success of new dedicated bifurcation stent technologies and for the evaluation at follow-up of potential predictors of stent thrombosis, including stent malapposition, stent under-expansion and stent-edge dissection. The development of 3D OCT enables better evaluation of coronary anatomy, especially of side branch ostium, that is difficult to visualize by 2D OCT.