Inclusive public dialogue about issues of concern to science and society can democratise and widen the knowledge base for decision-making so scientific research and developments are made accountable to citizens’ priorities. This participatory model of science communication is not yet widely practiced. More research is needed into how to make such communication effective. Formative audience research can inform a communication strategy’s design to meet its objectives effectively and enhance its relevance to participants’ needs and communication preferences. However, audience research designs based on transmission models are inadequate for the participatory objectives of public dialogue. They must therefore be adapted. This dissertation proposes how audience research should be designed and conducted when the objective of communication is public dialogue about science, such as biotechnology. The methodology involves building an evaluation framework from the literature and applying this to a case of applied research. Four sub-questions are addressed. First, audience research and participatory development communication literature is reviewed to propose how audience research should be designed and conducted for public dialogue broadly. Second, literature on public engagement about science is analysed for the challenges in public dialogue about science and the implications for audience research. Third, a set of guidelines is presented for evaluating the appropriateness of audience research for public dialogue about science. Finally, these guidelines are used to evaluate a case of qualitative audience research commissioned by the Public Understanding of Biotechnology (PUB) programme, judging the appropriateness of its design to the communication objectives and extracting further lessons for audience research. The findings present a “double-dialogical” approach to audience research, where the research methods and the information elicited reflect dialogical objectives. This approach emphasises listening over telling, building relationships over interrogating targets, and optimising inclusivity and diversity in identifying participants, framing issues, and selecting channels and spaces for deliberative dialogue, wherein participation and information dissemination play complementary roles. Following these principles, audience research can build democratic foundations for public dialogue about science while recognizing the following challenges: the specialized and technical nature of science, the complexity of issues, the power of commercial interests, the need for social accountability, low motivation and interest amongst publics, and the resistance of technical experts and decision-makers towards dialogue. A framework of guidelines is offered for designing and evaluating audience research for public dialogue about science, structured around 5 interrelated elements: WHY – clarifying the objectives of communication and audience research; GENERAL – overall research design considerations; WHO – conceptualizing and investigating dialogue participants; WHAT – framing issues from multiple perspectives; and HOW – identifying spaces and channels for public dialogue. Applying the framework to the case study demonstrates the guidelines’ usefulness for evaluation purposes, grounds the study in an actual case of audience research and extracts lessons for future applications. The framework succeeds in judging the appropriateness of the study’s design for its purpose. The study contributes to the search for effective means of public engagement by proposing practical guidelines for the first steps of such a process, a methodological praxis for audience research that can be useful in scholarly and practitioner communities and can be refined and adapted for various contexts.