Multisensory environments facilitate behavioral functioning in humans. The redundant signal effect (RSE) refers to the observation that individuals respond more quickly to stimuli when information is presented as multisensory, redundant stimuli rather than as a single stimulus presented to either modality alone. Our studies show that the disinhibiting effects of alcohol are attenuated when stop signals are multisensory versus unisensory. The present study expanded on this research to test the degree to which multisensory stop signals could also attenuate the disinhibiting effects of alcohol in those with attention-deficit hyperactivity disorder (ADHD), a clinical population characterized by poor impulse control. The study compared young adults with ADHD with healthy controls and examined the acute impairing effect of alcohol on response inhibition to stop signals that were presented as a unisensory stimulus or a multisensory stimulus. For controls, results showed alcohol impaired response inhibition to unisensory stop signals but not to multisensory stop signals. Response inhibition of those with ADHD was impaired by alcohol regardless of whether stop signals were unisensory or multisensory. The failure of multisensory stimuli to attenuate alcohol impairment in those with ADHD highlights a specific vulnerability that could account for heightened sensitivity to the disruptive effects of alcohol.