Adolescents spend a high proportion of their leisure time in sedentary behavior, which is associated with adverse physical and mental health outcomes. Exploring factors associated with leisure-time sedentary behavior (LTSB) is important for the development of targeted interventions. The aim of this study was to explore associations between cannabis use and LTSB in adolescents from 24 low- and middle-income countries. Data from the Global School-based Student Health Survey were analyzed. Data on past month cannabis use and LTSB during a typical day were collected. Multivariable logistic regressions were conducted to assess the associations. Among 94,035 adolescents aged 12-15 years [age = 13.7 ± SD 0.9 years; 49.2% female], the prevalence of high LTSB (≥3 h/day) was 26.6%, while 2.8% used cannabis at least once in the past 30 days. In adjusted analyses, compared to those who did not consume cannabis in the past 30 days, the OR (99%CI) for high LTSB among those who used cannabis 1-2 times, 3-9 times, 10-19 times, and ≥20 times were 0.89 (0.58-1.35), 1.96 (1.26-3.07), 1.97 (0.71-5.47), and 2.34 (0.95-5.78), respectively (test for trend p < 0.01). Our data suggest that frequent cannabis use is associated with increased odds for being more sedentary in adolescence. Future longitudinal data are required to confirm/refute the findings to inform public health campaigns.