Abstract The coronavirus crisis has negated the widely held post-Cold War narrative that the rise of non-state actors like non-governmental organizations, social movements and firms would end up supplanting states as the main actors on the international stage. States were the first responders to emerging health-related transboundary crises before the great strides of the 19th and 20th centuries to institutionalize health cooperation. Two decades into the 21st century, the world and state-level pandemics preparedness were exposed. The pandemic wreaked havoc on all states, notwithstanding their military and economic capabilities. It surpassed power asymmetries prevailing in the community of states. Among the many purposes of International Relations (IR) theories, include an attempt to explain and predict patterns of national behaviours or understand the world “inside the heads” of actors. What, then, can we learn from IR theories about the need for states to cooperate, and why was such cooperation not forthcoming, especially during the initial phases of the outbreak? Why was the initial global response so shambolic and largely inward-looking and uncoordinated? To answer these questions, the article draws insights from various IR theoretical strands and the ensuing structural, state and individual-level explanations of various actors’ responses to the COVID-19 pandemic.