The internet provides ample opportunities for romantic partners to interact, sometimes in a harmful manner. The use of technological applications to express excessive controlling and monitoring behaviours and verbal aggression towards a partner is called cyber dating abuse (CDA). Although some research has already studied the prevalence and nature of CDA, there are still three important knowledge gaps. First, to date, there is no consensus on how CDA should be conceptualised and operationalised. Second, the relation between CDA and its offline extension, psychological partner violence (PPV), is still largely unexplored, leaving questions about their co-occurrence and expression. Third, previous research has not yet identified determinants of CDA and PPV whilst taking situational characteristics into account. One theory that seems appropriate to identify these determinants is the situational action theory. The proposed research will address the three research gaps through the following approaches: 1) literature and focus group research to form a comprehensive conceptualisation and concordant operationalisation of CDA; 2) survey research to validate this CDA scale and examine the relation between CDA and PPV, and 3) survey research to assess the applicability of situational action theory to identify determinants of CDA and PPV. The findings of this proposal will provide important insights for partner violence prevention and intervention strategies, and future research.