Cigarette smoking remains a significant public health concern, particularly among adolescents. This study aimed to assess adolescents' knowledge of the risks associated with smoking in Scotland and explore the factors influencing this knowledge. A cross-sectional analysis was conducted using data from the 2018 Scottish Schools Adolescent Lifestyle and Substance Use Survey. The sample included 23 365 adolescents from Secondary 2 (n = 12 558) and Secondary 4 (n = 10 807). Demographic, behavioural, contextual, and health-related factors were examined as predictors of smoking risk knowledge, with a cumulative knowledge score based on responses to seven smoking-related questions. Poisson regression was used to examine associations between predictors and cumulative knowledge scores, and adjusted incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were reported. Overall, 38.2% (n = 8928) of participants answered all questions correctly, with a median score of 6 (IQR: 5-7). While 83.6% (n = 19 540) scored at least 5, knowledge gaps remained, particularly concerning the risks of light smoking. Boys had lower scores than girls (IRR = 0.97, 95% CI: 0.96-0.97, P < .001), and adolescents from less deprived areas scored higher than those from more deprived areas (IRR = 1.02, 95% CI: 1.01-1.03, P = .006). Non-smokers had higher scores than smokers (IRR = 1.08, 95% CI: 1.05-1.10, P < .001), and adolescents confident in accessing health information scored significantly higher (IRR = 1.13, 95% CI: 1.11-1.15, P < .001). Peer influence was evident, as adolescents with friends who smoked had lower scores (IRR = 0.96, 95% CI: 0.94-0.98, P < .001). Adolescents in Scotland generally understand the risks of cigarette smoking, but notable gaps persist, especially regarding dangers of light smoking.