Abstract. The German Site Selection Act for a Nuclear Repository of 2017 aims, among other objectives, to find a solution that is supported by a broad social consensus and can thus also be tolerated by those affected. Public participation is considered indispensable when planning and building a nuclear waste repository today. However, what is now even laid down by law has taken some time to emerge. The roots of today's guiding principles on public involvement lie first of all in the nuclear energy controversy of the 1970s and 1980s, which marked the first major societal conflict about technology in (West) Germany and, in terms of its consequences, has shaped the course of events up to the present day. Much of the experience with public engagement, its pitfalls and chances, has been largely forgotten. This paper seeks to address the present lack of knowledge about past government-funded public engagement on nuclear energy. It presents, for the first time, key findings from a 3-year interdisciplinary collaborative research project, funded by the Federal Office for the Safety of Nuclear Waste Management (BASE), on Germany's first information and dialogue campaign on this topic, the “Citizens' Dialogue on Nuclear Energy” (“Bürgerdialog Kernenergie”), which ran from the mid-1970s until the early 1980s. This research is based on comprehensive archival work in numerous state and non-state archives across Germany, a vast array of published materials, and oral history interviews. The paper will discuss why the campaign was started, which (international) models it drew on, which instruments it relied on, and which obstacles and dilemmas it faced. It will present where and to what extent the campaign was able to achieve its goals and where – and why – it failed. The “Citizens' Dialogue” was initially nationwide in scope. From 1977 onwards, activities primarily focussed on the region around Gorleben, where West Germany's nuclear waste repository was initially planned to be located (this decision being finally revoked in 2020). The paper argues that the government-funded campaign was based on two assumptions, which shaped its structure. First, relying on the then conventional knowledge deficit model, governments and experts assumed that citizens needed to be better informed to accept the need for nuclear expansion and lose their supposedly irrational fears regarding nuclear safety. Second, social democratic governments in Europe viewed the involvement of citizens in debates about technology, quality of life and planning for the future as new democratic territory. Juxtaposing past and present experiences with government-funded public engagement, the paper seeks to extract and discuss lessons that may be drawn from the history of past public engagement for the search for a new repository site – in Germany and elsewhere.