Without smoke-free legislation in Wuhan, China, we investigated secondhand smoke (SHS) exposure at home, school, and public places for never-smoking school-going adolescents in 2019. A cross-sectional study was carried out within the Global Youth Tobacco Survey (GYTS) framework. Weighted univariate, bivariate and multivariable analyses were conducted. The prevalence of SHS exposure among never-smoking adolescents at home, school and public places was 25.7%, 31.9% and 48.9%, respectively. Multivariable logistic regression analysis showed that parents smoking, peers smoking and observing teachers smoking in school were all significantly related to a higher probability of SHS exposure at home, school, and public places. Never-smoking adolescents who had smoking parents had 14 times (adjusted odds ratio [aOR], 14.00; 95% confidence interval [CI], 11.37–17.24) higher odds of SHS exposure at home; Never-smoking adolescents who observed teachers smoking in school had about 10 (aOR = 9.76; 95% CI = 7.13–13.36) and four times (aOR = 3.55; 95% CI = 2.77–4.55) higher odds of SHS exposure in school and public places, respectively. Adopting comprehensive smoke-free legislation in public places and smoke-free home rules and implementing and supervising smoke-free school policies may further reduce SHS exposure among adolescents.