Heidrun åm argues in her essay that policy studies can learn much from Science and Technology Studies (STS). STS concepts like co-production can help to explicate the mutually reinforcing explanatory power of STS and Critical Policy Studies (CPS) more systematically. ‘Co-production’ in particular can be a necessary reminder for policy analysts of the role of matter in the midst of discourse. åm shows the value of applying a co-productionist perspective together with a poststructuralist policy analysis along a study of voluntary nanotechnology regulations. These were adopted in a context of uncertainty, when little evidence of risks in nanomaterials was available. While a strong demand to pre-empt public resistance might have been a driver for developing nanotechnology regulations, regulations’ particular form can only be explained by taking into account nanotechnology’s ambiguity. Thus, the technology itself was an important element in the co-production of existing nanotechnology regulations.