Background Protruding aortic plaque is known to be associated with an increased risk for future cardiac and cerebrovascular events. However, the relationship between protruding aortic plaque and coronary plaque characteristics has not been systematically investigated. Methods and Results A total of 615 patients who underwent computed tomography angiography, and preintervention optical coherence tomography imaging were included. Coronary plaque characteristics were compared to evaluate coronary plaque vulnerability in patients with protruding aortic plaque on computed tomography angiography. 615 patients, the 186 (30.2%) patients with protruding aortic plaque were older and had more comorbidities such as hypertension, chronic kidney disease, and a prior myocardial infarction than those without. They also had a higher prevalence of coronary plaques with vulnerable features such as thin‐cap fibroatheroma (85 [45.7%] versus 120 [28.0%], P <0.001), lipid‐rich plaque (165 [88.7%] versus 346 [80.7%], P =0.014), macrophages (147 [79.0%] versus 294 [68.5%], P =0.008), layered plaque (117 [62.9%] versus 213 [49.7%], P =0.002), and plaque rupture (96 [51.6%] versus 111 [25.9%], P <0.001). Patients with protruding aortic plaque experienced more major adverse cardiac and cerebrovascular events, including all‐cause mortality, nonfatal acute coronary syndromes, and stroke (27 [14.7%] versus 21 [4.9%], P <0.001; 8 [4.3%] versus 1 [0.2%], P <0.001; 5 [2.7%] versus 3 [0.7%], P =0.030; and 5 [2.7%] versus 2 [0.5%], P =0.013, respectively). Conclusions The current study demonstrates that patients with protruding aortic plaque have more features of coronary plaque vulnerability and are at increased risk of future adverse events.