Purpose - The purpose of this paper is to examine the nature of union responses to globalisation and, in particular, the global financial crisis; the consequences of the financial crisis for workers; and lessons from the experience. Design/methodology/approach - The authors examined numerous union statements, declarations, reports and actions as well as extensive documentary evidence from other sources. The focus was on the behaviour of supranational trade unions, including the European Trade Union Confederation, the International Trade Union Confederation and Global Unions. Findings - The supranational unions' methods gradually shifted in the 2000s from reliance on institutional politics to collaboration with broader alter-globalisation protest movements, though this carried risks. The global financial crisis appeared to be a strategic opportunity for trade unions, but while they developed sophisticated policy packages, they were unable to change the behaviour of global institutions. This accentuated the shift in union strategy. Governments initially set aside free market ideology for stimulus packages, but failed to regulate to prevent future crises. Workers bore the brunt of the crisis. The experience highlighted the contradictions facing unions dealing with global issues. Practical implications - The outcomes of crises depend on the actions, strategies and prior strengths of the parties. Different outcomes emerged from prior crises and may emerge from future ones. Originality/value - Few studies have examined the role of supranational unions in the context of the financial crisis. A clearer understanding of the weaknesses of and impediments to supranational union responses may increase the likelihood that future crises will be better understood and be followed by more effective responses.