BackgroundSexual violence (SV) is a significant, global public health problem, particularly among young adults. Promising interventions exist, including prosocial bystander intervention programs that train bystanders to intervene in situations at-risk for SV. However, these programs suffer from critical weaknesses: (1) they do not address the proximal effect of alcohol use on bystander decision-making and (2) they rely on self-report measures to evaluate outcomes. To overcome these limitations, we integrate new content specific to alcohol use within the context of prosocial bystander intervention into an existing, evidence-based program, RealConsent1.0. The resulting program, RealConsent2.0, aims to facilitate bystander behavior among sober and intoxicated bystanders and uses a virtual reality (VR) environment to assess bystander behavior in the context of acute alcohol use.MethodsThis protocol paper presents the design of a randomized controlled trial (RCT) in which we evaluate RealConsent2.0 for efficacy in increasing alcohol- and non-alcohol-involved bystander behavior compared to RealConsent1.0 or to an attention-control program (“Taking Charge”). The RCT is being implemented in Atlanta, GA, and Lincoln, NE. Participants will be 605, healthy men aged 21–25 years recruited through social media, community-based flyers, and university email lists. Eligible participants who provide informed consent and complete the baseline survey, which includes self-reported bystander behavior, are then randomized to one of six conditions: RealConsent2.0/alcohol, RealConsent2.0/placebo, RealConsent1.0/alcohol, RealConsent1.0/placebo, Taking Charge/alcohol, or Taking Charge/placebo. After completing their assigned program, participants complete a laboratory session in which they consume an alcohol (target BrAC: .08%) or placebo beverage and then engage in the Bystanders in Sexual Assault Virtual Environments (BSAVE), a virtual house party comprising situations in which participants have opportunities to intervene. Self-reported bystander behavior across alcohol and non-alcohol contexts is also assessed at 6- and 12-months post-intervention. Secondary outcomes include attitudes toward, outcome expectancies for, and self-efficacy for bystander behavior via self-report.DiscussionRealConsent2.0 is the first web-based intervention for young men that encourages and teaches skills to engage in prosocial bystander behavior to prevent SV while intoxicated. This is also the first study to assess the proximal effect of alcohol on bystander behavior via a VR environment.Trial registrationClinicaltrials.gov, NCT04912492. Registered on 05 February 2021