The concept of ‘public science’ has been fruitfully used to indicate the intricate interrelatedness of science and society. In studies of knowledge and its publics, however, technology has been routinely subsumed under science and the distinctive nature of technical knowledge neglected. We are aiming in this article at conceptualizing the public nature of technologies. First, we start with surveying the literature on public science. Second, we scrutinize various conceptual approaches to better understand the social and cultural factors embedded in technologies. In so doing, we reflect upon the twentieth-century history of technologies as public things. Third, we focus on nuclear energy in Europe as an exemplary case of a large-scale technology which has been shaped as part of public culture. We suggest that the specificities of the nuclear as a publicly shaped societal entity can be understood as an example of the wider category we propose to call ‘public technologies’.