Alcohol use in the Unites States is a public health crisis that costs the U.S. health care system $249 billion annually. However, only about 10% of individuals with alcohol use disorder receive treatment and a significant proportion will relapse within one year of treatment. These trends are especially troubling among young adults who exhibit the highest prevalence of alcohol use disorder among U.S. cohorts but are least likely to seek treatment. Disruption of the body’s stress response system has been identified as a key factor that contributes to risk of relapse and innovative and widely accessible interventions that help individuals cope with acute stress during early recovery are urgently needed. Music listening has been shown to elicit activity in areas of the brain associated with reward and emotions and has thus been proposed to be an effective tool for emotion regulation and stress management. However, no relapse interventions have capitalized on the potential of music listening to rehabilitate these systems. There is a lack of evidence that music-listening can influence emotion regulation, and ultimately reduce acute stress, in real-world settings and uncontrolled environments. We aim to develop the first just-in-time adaptive music-listening intervention to regulate emotions and reduce stress among individuals within the first 90 days of detoxification from alcohol use. We design the study with two phases to address three aims: For Aim 1, we will conduct formative research with a sample of young adults who have received treatment for alcohol use disorders and are within 90 days of sobriety to identify features of music selections that are most effective in reducing stress in real-world, ambulatory settings; For Aim 2, we will focus on developing mobile health technology that uses passive sensing and machine learning to automatically predict moments of heightened stress in real-time and suggest specific musical selections when stress is detected. During Aim 3, we will test the feasibility of a novel music-listening intervention among a second sample of young adults who have received treatment for AUD and are within 90 days of sobriety. The goal of our proposed study is to provide a cost-effective and accessible music-listening intervention to support the increasing population of individuals struggling with relapse risk during early stages of recovery from alcohol use disorder. This research will provide a critical foundation upon which large-scale efficacy trials of adaptive just-in-time music interventions can be conducted.