A variety of risk factors for adolescent smoking have been identified and explored, but few have focused on the influence of second-hand tobacco smoke on smoking initiation. Consideration of exposure to secondhand tobacco smoke, and the influence this has on smoking initiation, is particularly important in the home and the school environment, as this is where young people spend the majority of their time. The Liverpool Longitudinal Smoking Study (LLSS) is a unique study funded by the Roy Castle Lung Cancer Foundation, established to investigate children’s knowledge, experiences and attitudes towards smoking using a wide range of innovative tools. The LLSS has tracked a single birth cohort of 253 young people from age five throughout their compulsory education. Using quantitative data from the secondary school phase of the study, this paper aims to address: Whether environmental smoking indicators (i.e. home smoking rules, perceived peer smoking and being in other smoky environments) predict (a) adolescents smoking trial, and (b) whether they have smoked in the last week. Data were analysed using Chi-Squared tests to test the strength of association, and logistic regression analysis to estimate the adjusted odds ratio and 95% confidence interval for each potential risk factor. Children who attended schools with higher deprivation scores and had household rules that advocated smoking were found to be significant predictors of smoking trial. Significant predictors of weekly smoking were found to be higher home deprivation scores and household rules that advocated smoking. Although public smoking bans may prove successful in reducing adolescent smoking trial, our findings suggest there is a need to target socially deprived groups. Smoke-free home interventions should be used and supplemented by school-based initiatives to reduce adolescent transition to regular smoking.