Natural and man-made disasters are common locally and at the international level. These disasters in form of flooding, earthquakes, volcanoes and soil erosion have caused monumental damage to lives and properties. This study focused on multinational cooperation in the management of flood disasters in Southern Nigeria (2012-2023). The study area comprised Anambra, Edo, Delta, Kogi, Rivers and Bayelsa States that are perennially flooded. A sample size of 1320 federal staff was chosen through the simple random sampling method. States and federal establishments were purposively selected. The theoretical framework was anchored on Structural-Functional theory and System theory. The study employed empirical survey as research design. Data was gathered through the use of questionnaire method which was complemented by in-depth interviews. Data was analysed using simple percentages to answer the research questions. The study found out that multinational cooperation with National Emergency Management Agency (NEMA) has impacted positively on the effective management of flood disasters in the study area. However, both the climate change and the non-completion of the Hausa-Fulani dam in Adamawa State in Nigeria have contributed to the flooding of the study area. The periodic release of flood water from Lagdo dam in Cameroon also lead to perennial flooding of this study area in Nigeria. The study recommended a quick completion of Hausa-Fulani dam by the Federal Government of Nigeria; and full cooperation of Nigeria with Cameroon on the release of water from Lagdo dam in Cameroon.