Dating violence is defined as the tendency to force a person, to establish power and control over a person. Dating violence is a public health problem for all countries in the world (WHO, 2021; Kerman \& Öztürk, 2022). According to the results of studies conducted with university students; more than 70% of students are exposed to dating violence (Schuster et al., 2016; Toplu-Demirtaş \& Fincham, 2020). In addition, it is stated in studies that dating violence starts before the age of 25 (Peterson et al., 2018; Park \& Kim, 2021). Young people exposed to violence may have difficulty seeking help, hide the violence, and feel obliged to maintain the relationship (Park \& Kim, 2021). Studies have shown that college students exposed to dating violence experience many negative physical and mental problems, including physical injuries, depression, anxiety, decreased academic performance, and drug and alcohol abuse (Choi et al., 2017).

One of the ways to reduce the risk of dating violence is to focus on other bystanders. It is seen that programs developed to prevent violence are shaped around bystander intervention (Banyard et al., 2019). Bystander intervention, an evidence-based intervention to prevent dating violence, is defined as "an initiative that focuses on adolescents or young adults who have the necessary skills and self-efficacy to safely intervene when they witness dating violence and sexual violence" (Storer, 2016). Bystanders can contribute to risk reduction directly (e.g. by calling security, intervening directly) or indirectly (e.g. by challenging negative attitudes towards dating violence) when dating violence occurs (Amar et al., 2015; Banyard et al., 2019; Debnam and Mauer, 2019; Finnie et al., 2022). Recent studies have found that bystander intervention programs applied to young people produce statistically significant results in the areas of (1) knowledge about dating violence (prevalence, definitions, etc.); (2) attitudes towards dating violence (decrease in sexist attitudes, decrease in denial of violence as a problem, increase in confidence to intervene, increase in intention to intervene, increase in students' self-efficacy to take action against violence, etc.) and (3) behavioral change (decrease in violence perpetration rate, etc.) (Amar et al. 2015; Jouriles et al. 2018; Peterson et al. 2018). ) and (3) behavior change (decreased rate of violence perpetration, etc.) (Amar et al. 2015; Jouriles et al. 2018; Peterson et al. 2018).

Nurses are one of the first intervention health professionals in the care of individuals exposed to violence. Providing direct care to the individual subjected to violence and advocating for resources focused on preventing violence is one of the responsibilities and roles of nursing care. It is stated that mental health nurses can apply bystander education principles in prevention programs that aim to change community norms regarding violence (Amar et al. 2012; Kerman \& Öztürk, 2022). It is stated that it is important for nursing students, who will be among the health professionals of the future, to develop knowledge, skills, and attitudes about what to do when they witness violence (Barroso-Corroto ve ark., 2022). There are different bystander intervention programs used to prevent dating violence in the literature (Debnam \& Mauer, 2019). However, there is no bystander intervention program developed for dating violence for university students in Turkey. Accordingly, this study aims to evaluate the effectiveness of the bystander intervention program developed for dating violence in nursing students.