Non-physical intimate partner violence (NPIPV) encompasses emotional, psychological, and financial abuse within intimate relationships, increasingly recognized for its subtle yet pervasive impact. This study investigates demographic and situational influences on observers' responses to NPIPV scenarios, involving 381 participants (54 % female). Utilizing factorial vignette designs, we analysed how manipulating victim and perpetrator sex affected evaluations of abuse, intervention likelihood, and recommendations for professional support and police reporting. Results from ordinal logistic regression indicate significant associations: observer ethnicity influenced abuse perceptions, with lower odds among mixed and Black ethnicities compared to White participants. Interactions between observer sex and victim-perpetrator dyads revealed nuanced perceptions. Additionally, observer sex and ethnicity influenced support-seeking recommendations, while reporting to police recommendations varied by victim-perpetrator characteristics and marital status. These findings emphasize the necessity of accounting for demographic factors in addressing NPIPV and devising targeted interventions for improving access to health and criminal justice services.