Acute coronary syndrome mostly arises from rupture or erosion of a vulnerable plaque. Vulnerable plaques typically appear as lipid-rich plaques with a thin cap, called thin-cap fibroatheromas. Various intracoronary imaging techniques can be used to detect vulnerable plaques, such as intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS), each visualizing different high-risk plaque characteristics. IVUS and its post-processing techniques, such as virtual histology IVUS, can primarily be used to identify calcified and soft plaques, while OCT is also able to quantitatively measure the cap thickness. The addition of NIRS allows the exact measurement of lipid content in the plaque. Non-invasive imaging techniques to identify vulnerable plaques, such as computed tomography, are less often used but are evolving and may be of additional diagnostic use, especially when prophylactic treatments for vulnerable plaques are further established. Pharmacological treatment with lipid-lowering or anti-inflammatory medication leads to plaque stabilization and reduction of cardiovascular events. Moreover, the implantation of a stent or scaffold for the local treatment of vulnerable plaques has been found to be safe and to stabilize high-risk plaque features. The use of drug-coated balloons to treat vulnerable plaques is the subject of ongoing research. Future studies should focus on non-invasive imaging techniques to adequately identify vulnerable plaques and further randomized clinical studies are necessary to find the most appropriate treatment strategy for vulnerable plaques.