The proliferation of corporate codes of conduct generates both alliance and tension between trade unions and NGOs that deal with workers’ rights in the global economy. Alliance, because trade unions and NGOs share a common desire to halt abusive behaviour by multinational companies and a broader goal of checking corporate power in the global economy. Tension, because unions and NGOs have differing institutional interests, different analyses of problems and potential solutions, and different ways of thinking and talking about social justice in the global economy. There are fears that codes of conduct may be used to undermine effective labour law enforcement by governmental authorities and undermine workers’ power in trade unions. The substance behind the rhetoric on this new generation of corporate codes of conduct is certainly open to question. However, this paper argues that, given unions’ weak presence in the global assembly line and the rapid-response capabilities of many NGOs, such codes are a valuable asset. Trade unions and NGOs still have more in common with each other than either has with corporations, governments, or international organisations that see free trade and free-flowing capital as the solution to low labour standards. But both need to be clear-eyed about their differences and their proper roles as they navigate the opportunities and challenges that lie ahead.