Bullying victimization remains a pressing concern to the health and development of U.S. adolescents. Victims of bullying face threats to their safety and education. Hence, interventions are needed to prevent bullying and equip others to intervene in bullying situations. Prior research has examined preventive interventions with little consideration of promotion-tailored, peace-encouraging, interventions. Further, there is a need to test whether people’s motives toward preventive and promotive actions may fit with certain intervention tracks. Here, we tested an upstander approach consisting of a universal assembly presentation with promotion-oriented education (Promote Caring) and prevention-oriented education (Say Something), as well as a tailored 150-minute workshop (Upstanding for Promotion-Prevention). High school students (n = 388; 53.9% girls) participated in the study with a control group (n = 335) and intervention group who self-selected to experience upstanding for peace promotion (n = 15) or upstanding for bullying prevention (n = 35). Students in the prevention-tailored track reported stronger safety beliefs (violence prevention beliefs and care promotion beliefs) than students in the control group and endorsed using more defending actions than control-group students. Students’ gain, non-gain, and loss motivations moderated ties between upstanding track involvement and post-test safety beliefs, barriers to upstanding, and defending behaviors.