The regulation of nanomaterials is still surrounded by scientific uncertainty regarding their potential human health risks. It is therefore useful to consider learning approaches in the process of regulation. Effective regulation is conceptualised with regard to collaborative activities of state and non-state actors that enable mutual learning regarding the health risks of nanomaterials. A theoretical framework is offered for studying learning processes in the area of occupational safety and health. Drawing on the network governance literature, three learning types (namely substantive, strategic, and institutional learning) are distinguished. Analytical conditions are proposed and applied to the case of nanomaterials in Germany, thereby offering insights into learning processes in industry-initiated collaborative activities. It is concluded that the development of trust among network collaborators is decisive for learning processes. Accordingly, a proposal for research into specific stages of trust development is made.