Exposure to cigarette advertising can increase the likelihood of youth smoking initiation and may encourage people who already smoke to continue. Requiring prominent, graphic warning labels could reduce these effects. We test whether graphic versus text-only warning labels in cigarette advertisements influence cognitive and emotional factors associated with youth susceptibility to smoking and adult intentions to quit. We conducted two randomized, between-subjects experiments with middle-school youth (n = 474) and adult smokers (n = 451). Both studies employed a two (graphic or text-only warnings) by two (advertisements with social cues or brand imagery) factorial design with a fifth, offset control group (social cue advertisements with the current US Surgeon General's Warning). Graphic warnings outperformed text-only warnings in reducing visual attention to the advertisement, generating visual attention to the warning and arousing more negative affect. Graphic warnings also reduced the appeal of cigarette brands among youth relative to social cue advertisements with the Surgeon General's warnings. None of the warnings (graphic or textual) influenced health risk beliefs. Graphic warning labels on cigarette advertisements appear to have effects similar to those observed on cigarette packs in previous work, with an added benefit of reducing cigarette brand appeal among youth.