The public sphere, reflected by the public discourse, is an important domain for the legitimation of technology. In the institutional literature, four pillars of legitimacy are distinguished: normative, cognitive, regulative, and pragmatic. The aim of this study was to investigate to what extent these pillars can be used as a framework for analysing the legitimation of technological innovations in the public discourse. We conducted a qualitative media analysis of the case of GM food in the Netherlands, analysing 287 articles from nine Dutch newspapers in the period of 1996-2016. The results show that the pillars provide insight into legitimacy in a multi-dimensional way and serve as a structure for the dynamics of legitimation processes. Regarding GM food, the public debate was pre-dominantly negative, with a strong focus on the normative pillar. Emotional rhetoric exceeded knowledge and understanding (cognitive pillar) of GM food. The regulative and pragmatic pillars were hardly addressed.