This contribution looks at the use of the ‘consensus’ argument in 140 amicus curiae briefs submitted by non-governmental organisations (NGOs) to the Grand Chamber of the European Court of Human Rights. The analysis reveals that a ‘consensus’ argument is often wielded with creativity in their submissions, both regarding the types of consensus and the sources on which they are based. NGOs’ briefs, therefore, contribute to a further expansion of different types of consensus manifestations. Considering the multiple criticisms levelled at the consensus argument, this contribution also observes that NGOs’ briefs sometimes lack methodological rigour and rarely provide for a justification as to the relevance of the consensus argument. This might come as a surprise, coming from actors generally thought as putting forward a universalist understanding of human rights, and this chapter proposes a few hypotheses by way of explanation.