To design regulatory policies, agencies depend on information from the industries they are tasked to regulate. Therefore, agencies can organise consultations with the aim of obtaining information from different perspectives. This article focuses on stakeholder diversity in agency public consultations. We ask to what extent is information provided by stakeholders other than the regulated sector, such as other business interests, experts or nonbusiness interests? Stakeholder diversity is relevant as it may prevent agencies to become exposed to one-sided information and capture by specialised interests. Are there consultation design factors that foster consultation diversity? Or, is (a lack of) consultation diversity structurally shaped by the context in which an agency operates? Analysing a wide range of public consultations organised by European Union regulatory agencies indicates that most information agencies receive via consultations comes from regulated interests and that the limited participation of nonregulated interests is highly tenacious.