Farm animal welfare has become an important issue for the European public, especially in the last two decades when a number of crises (eg Bovine Spongiform Encephalopathy and Avian Influenza) have affected farm animal populations. Public concern about this issue led the European Union to fund the Welfare Quality® project. This project aimed to develop a protocol for assessing animal welfare on farms and at slaughter plants, to identify the main animal welfare problems, and to address possible welfare improvement strategies. In fulfilling these aims, the Welfare Quality® project incorporated inputs from both science and society. This was crucial, as the public perception of what constitutes ‘animal welfare’ sometimes differs from animal science-based definitions. Furthermore, these differences are often interwoven with broader variations in ethical- and value-based understandings about human/non-human animal relationships. This paper presents the steps that we adopted to establish a dialogue between science and society during the construction of the Welfare Quality® assessment protocols. This dialogue involved numerous interactions between animal scientists, social scientists and members of the public. These interactions took several forms, including: meetings, conferences, workshops, websites, newsletters, interviews, focus groups, and citizen and farmers juries. Here, we address four key moments within this dialogue: the development of the initial list of twelve welfare criteria; the consumer focus groups; the development of the Welfare Quality® scoring system; and the citizen juries. In particular, we focus on the results of the focus groups and citizen juries. The focus groups were conducted in France, Italy, Sweden, The Netherlands, the United Kingdom, Norway, and Hungary and the citizen juries were carried out in Italy, the United Kingdom, and Norway. Drawing on this research, we highlight the similarities and differences between societal understandings of farm animal welfare and the views of scientific experts. Furthermore, and crucially, we outline how the animal scientists took account of societal opinion when developing their farm animal welfare assessment tools.