Understanding the correlation between demographic, socio-economic, and lifestyle factors with e-cigarette use, cigarette smoking, and dual use is essential for targeted public health interventions. This study examines the prevalence of these behaviors in Scotland and identifies the associated factors. We conducted a repeated cross-sectional analysis of the Scottish Health Survey data from 2017 to 2021, leveraging data from 12,644 participants aged 16 and older: 2271 cigarette smokers, 687 e-cigarette users, 428 dual users, and 9258 never users. Weighted prevalences were calculated by age group, sex, and survey year, followed by weighted multinomial logistic regression to explore associated factors. The overall prevalences were 72.0% (95% CI 70.9–73.1) for never users, 18.9% (95% CI 17.9–19.9) for cigarette smokers, 5.5% (95% CI 5.0–6.1) for e-cigarette users, and 3.6% (95% CI 3.2–4.0) for dual users. From 2017 to 2021, cigarette smoking declined from 21.7% (95% CI 19.6–23.9) to 13.1% (95% CI 11.5–15.0), e-cigarette use from 6.5% (95% CI 5.4–7.8) to 4.8% (95% CI 3.6–6.4), and dual use from 3.7% (95% CI 2.9–4.6) to 2.7% (95% CI 1.9–3.7). Age was a critical factor, with the 25–34 age group more likely to use e-cigarettes (p = 0.007) and the 35–44 age group more likely to engage in dual use (p = 0.006) compared to the 16–24 age group. Males had higher odds of e-cigarette use than females (p = 0.031). White individuals had higher odds of using e-cigarettes (p = 0.023) and being dual users (p = 0.017) compared to non-whites. Previously married individuals had higher odds of dual use than singles (p = 0.031). Larger household sizes were linked to reduced odds of all three behaviors (p = 0.001). Rural residents were less likely to use e-cigarettes compared to urban residents (p = 0.025). Higher education correlated with lower odds of all three behaviors (p = 0.001). Manual occupation increased the likelihood of dual use (p = 0.042). Lower income and higher deprivation significantly increased the odds of all three behaviors (p < 0.001). Excessive alcohol consumption was associated with increased odds of the three behaviors (p < 0.001). Poor sleep quality correlated with increased odds of dual use (p = 0.002) and cigarette smoking (p < 0.001). Adherence to physical activity guidelines was associated with reduced odds of all three behaviors (cigarette smoking p < 0.001, e-cigarette use p = 0.031, dual use p = 0.016). In conclusion, this study showed a decline in the prevalence of cigarette smoking, e-cigarette use, and dual usage from 2017 to 2021 in Scotland. Significant associations with demographic, socio-economic, and lifestyle factors highlight the need for targeted public health interventions.