The securitisation theory (ST) often gives rise to the debate on the positive and negative dimensions of security. ST is frequently quoted in this debate to explore what happens when threats are labelled as a security issue. The positive and negative points in the debate on ST are closely related to migration, environment, and health. However, like other international relations (IR) theories, the ST debate often fails to reflect the voices and experiences of different regional contexts. This article contributed to the securitisation debates by adding the perspectives and experiences of the Southeast Asia region by applying critical literature review analysis, using primary and secondary sources data collection. Although public health challenges are global phenomena, the way they are addressed may vary across geographical regions. The article reviews the consequences of securitising on contagious diseases in Southeast Asia as the region is often associated with distinctive political cultures that shape the governing norms. Securitisation has clearly made a positive impact on the health security cooperation in the region. Instead of encouraging state-centric thinking, the securitisation of health crises has prompted ASEAN countries to be more region-centric, ultimately challenging the regional norms that have historically obstructed cooperation across the nations. Keywords: ASEAN, health security, regional cooperation, securitisation theory, Southeast Asia. Cite as: Mohd Azmi, N. (2024). Securitising health crises on regional cooperation: Hindering or facilitating cooperation. Journal of Nusantara Studies, 9(2), 557-576. http://dx.doi.org/10.24200/jonus.vol9iss2pp557-576