Introduction <p>Public willingness to intervene in episodes of violence against women is shaped by multiple factors. While bystander responses have been widely studied in cases of sexual assault and intimate partner violence, less is known about reactions to violence involving socially marginalised women, such as those in prostitution, who often face additional barriers to support due to stigma and discrimination.</p> Objective <p>The current study analyses factors influencing individuals’ willingness to support the formal reporting of male-to-female episodes of violence, with particular attention to prostitution-related contexts.</p> Methods <p>A factorial survey was administered in 2022 to a sample of 1,598 respondents (51.6% women), each of whom evaluated a unique vignette depicting an incident of violence against a woman. Five dimensions were manipulated: the victim’s gender identity and nationality, the context of the incident, the type of violence, whether the abuse was reported, and the relationship between the victim and the respondent (friend <i>vs.</i> stranger). Respondents’ personal characteristics and attitudinal factors were also considered.</p> Results <p>Respondents generally supported the reporting of violence against women, with stronger support when the victim was a friend rather than a stranger, and when the incident occurred in a prostitution-related context compared to a non-prostitution context. Attitudinal factors, such as ambivalent sexism, rape myth acceptance, and attitudes towards prostitutes, influenced support.</p> Policy Implications <p>These findings highlight the need for interventions targeting sexist beliefs, rape myths, and harmful assumptions about prostitutes that may hinder bystander support. The study offers practical guidance for policymakers and practitioners in Spain aiming to strengthen public engagement in reporting violence against women across diverse social contexts.</p>