Gender based violence (GBV) is a global public health issue and a major feature in humanitarian emergencies. However, the phenomenon is not inevitable and can be predicted and prevented. In a context such as the Philippines, where GBV is widespread and there is a constant threat of natural hazards, strengthening the capacity of humanitarian responders to reduce the risks of GBV post disasters can contribute to preventing unnecessary suffering of affected populations. Yet, no previous research has looked at factors associated with the perpetration of GBV and strategies used by humanitarian actors to engage with men and boys to prevent these types of violence post disasters in the Philippines. The aim of this study is to enhance this knowledge and investigate; how can humanitarian actors in the Philippines work with men and boys to prevent the perpetration of GBV post disasters? The study adopts a qualitative research approach and based on a literature review and 18 key-informant interviews with humanitarian actors in the Philippines, it explores the current knowledge and practice on the topic. The material was analysed in relation to gender and feminist theory, the Ecological Model of risk factors of GBV, a primary prevention approach and the Spectrum of Violence Prevention. The study identifies a number of aggravating factors that seem to be associated with an increased risk of perpetration of GBV post disasters, such as men’s loss of a livelihood and lack of coping mechanisms. However, these factors are not the causes of GBV but these violent acts are deeply rooted in gendered power imbalances and rigid gender roles in the Philippines society. Ultimately, the study concludes that to effectively prevent the perpetration of GBV post disasters, long-term and effective multi-sectoral efforts between a wide range of actors are needed. In this work, humanitarian actors can play a key role to initiate change. The study suggests that humanitarian actors, within their existing activities, should seek to increase men’s access to safe spaces, peer support networks and mental health services, and support men to develop more elastic gender roles and non-violent coping mechanisms. Programmes should simultaneously increase women’s empowerment, the broader community’s support for social change and allow for dialogue to take place between women and men to synchronise their social transformations. Finally, the study notices that a rather heteronormative and binary understanding of gender seem to be present in the shared initiatives to prevent GBV post disasters. Hence, the study suggests that humanitarian actors should strengthen the capacity of their staff to apply a gender and norm-critical analysis in their work by incorporating these aspects in internal trainings.