[manuscript] Sexual Harassment Bystander Training Effectiveness: Experimentally Comparing 2D Video to Virtual Reality Practice [published version] Technology, Mind and Behavior (Forthcoming) [working version] VHIL Sexual harassment (hereafter, SH) is a dysfunctional workplace behavior, resulting in negative outcomes for individuals and organizations. Since #MeToo, companies have been innovating to increase the effectiveness of SH training by incorporating new content (e.g., bystander intervention skills) and new technology (e.g., virtual reality, hereafter VR). However, research has yet to determine the best practices or the effectiveness of these new innovations. The current study hypothesizes that SH bystander intervention training will be more effective when VR practice scenarios are used rather than 2D video practice scenarios. We argue that the increased presence (i.e., the perception that people and places in a virtual simulation are real) afforded by VR should better replicate bystander experiences in real SH situations, thereby allowing trainees to develop bystander skills in a more realistic practice experience than 2D video provides. We experimentally test our hypothesis in a laboratory setting (N = 100). Our results show that the VR practice condition differed from the 2D video condition by increasing trainees’ intentions to engage in indirect, non-confrontational, and widely applicable interventions (e.g., intervene by removing the target from the situation, approach the target to offer support later). However, our manipulation showed a negative effect on practice quantity (i.e., those in the VR condition explored fewer response options) and no effect on other operationalizations of training effectiveness (e.g., motivation to learn, knowledge, attitudes toward the training, intentions to directly confront the harasser, and intentions to formally report the harassment). Implications, limitations and directions for future research are discussed.