the canadian government’s efforts to prevent cannabis use among youth are warranted, as early cannabis use greatly increases risk of harm. although it is illegal, cannabis companies continue to advertise their products to youth, potentially influencing cannabis expectancies and use intentions. some youth groups may be more susceptible to advertising based on demographic risk factors (urbanicity, gender, ethnicity, age) and psychosis risk. ecological momentary assessment (ema) enables youth to track a range of phenomena, in vivo. using ema, this research describes: how cannabis advertising is reaching youth, how such exposures may impact cannabis expectancies and use intentions, and whether at risk (demographics, psychosis risk) youth groups are differentially impacted by cannabis advertising exposures. over a nine-day ema protocol, 120 youth aged 14-18 completed demographic and psychosis-risk questionnaires, captured cannabis advertising exposures, and rated their reactions (expectancies and use intentions) to exposure(s) and during two daily randomly issued (control) prompts. altogether, most (n = 85; 70.83%; range 1-30) youth reported being exposed to cannabis advertisements through various channels. using multilevel models, this study also found that advertisement exposure increased cannabis use intentions, while it did not increase cannabis expectancies. interaction effects for all demographic predictors and psychosis risk on expectancies and use intentions were also nonsignificant. [...]