This paper examines the labour standard-setting capacities of the EU and NAFTA. The social dimension to the EU is depicted as being organised along the principles of deliberative supranationalism. The North American Agreement on Labour Cooperation (NAALC), sometimes referred to as the Labour Side Accord, which is the labour standard-setting arrangement for NAFTA, is regarded as a tri-national institutional arrangement which grafts formal international procedures onto domestic labour market regimes. The paper seeks to describe and explain how the different types of activities in which the two social dimensions are engaged can be traced back to their overall institutional design. The paper argues that EU social policy is the stronger of the two arrangements and that NAALC has significant shortcomings. Yet it also argues that NAALC holds out interesting lessons for other regional trading blocs and other global experiments in labour market standard setting as its decentralised and `horizontal' character is more in keeping with the broad institutional design of these arrangements.