INTRODUCTION: Detrimental effects of secondhand smoke (SHS) exposure are well established; however, data on SHS exposure among adolescents in Kuwait are lacking. Hence, this study sought to estimate the prevalence of household SHS exposure among two samples of adolescents in Kuwait and assess its variation by socioeconomic status and parental education level. METHODS: Data from two large school-based cross-sectional studies were analyzed. Adolescents attending public middle (n=3864; aged 11-14 years) and high (n=1959; aged 14-19 years) schools throughout Kuwait were enrolled in 2016-2017, and parental self-reported household SHS exposure was ascertained. Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (APRs) and 95% confidence intervals (CIs) were estimated. RESULTS: Overall, 45.8% (1755/3836; 95% CI: 44.2-47.3%) of the enrolled middle school students and 51.6% (998/1936; 95% CI: 49.3-53.8%) of the enrolled high school students were exposed to household SHS. Among middle and high school students, the prevalence of household SHS exposure increased as maternal/paternal education level and family income decreased. Among middle school students, paternal educational attainment of middle school or less compared to bachelor's degree or higher was associated with 1.60 times (95% CI: 1.44-1.79) higher household SHS exposure. Similarly, in the sample of middle school students, the prevalence of household SHS exposure significantly increased from 35.8% among children from families reporting the highest household income to 50.5% among children from families with the lowest reported household income (p-trend<0.001). CONCLUSIONS: Household SHS exposure is substantially high among adolescents in Kuwait. Enrolled adolescents from families with low socioeconomic status or with low parental education level have the highest household SHS exposure. These findings highlight the need for national comprehensive tobacco control policies and increasing parental awareness of the impact of SHS exposure on children.