Background and Purpose— The purpose of this study was to analyze the association between morphological characteristics of human carotid plaques and patient’s sex, age, and history of neurological symptoms. Methods— The study included 763 atherosclerotic plaques from patients treated surgically for carotid stenosis between 2004 and 2013. Histological analyses of carotid plaques were performed to assess the type of plaque (American Heart Association classification), the stability of the plaque, the extent of calcification, inflammation, and neovascularization, as well as the deposition of collagen and elastin. According to the scale of outcome measurement, logistic regression, ordinal regression, and multinomial regression analyses were applied. All results were adjusted for common risk factors of atherosclerosis. Results— Male sex was associated with more cellularity (odds ratio [OR], 1.56; P =0.003), more inflammatory infiltrates (OR, 1.75; P <0.001), and more neovascularization (OR, 1.47; P =0.010), but less calcification (OR, 0.78; P =0.090). Symptomatic patients were more likely to have a lower amount of elastin (OR, 0.71; P =0.057). Higher age was associated with increased calcification (OR, 1.23; P =0.009). Unstable plaques were found more frequently in symptomatic patients (OR, 1.60; 95% confidence interval, 1.14–2.25; P =0.007). A multinomial regression model revealed that age, sex, and history of neurological symptoms were significantly associated with specific plaque types ( P =0.009, P <0.001, and P =0.017, respectively). Conclusions— Plaque morphology differed between men and women and varied with age. Certain types of plaques (VI and VI/VII) as well as unstable plaques were significantly associated with a history of neurological symptoms. Thus, individual approaches (eg, in detection of plaque hemorrhage or thin fibrous caps) especially based on sex and age should be considered to identify patients at increased risk of stroke.