Shaping one's own everyday life in the sense of sustainable development (SD) and participating in corresponding social processes call for the ability to make decisions in terms of SD. To promote this ability, this article focuses on the question of how pupils make decisions in the context of SD and which types of decision-making processes (DMP) can be identified. To this end, 27 pupils from various Swiss German schools were interviewed in this study using the thinking-aloud method. The data were analysed according to the method of empirically grounded type construction by Kelle and Kluge. This resulted in five types of DMP. Differences were particularly evident in the formulation and consideration of several options for action as well as in weighing them up. The heterogeneity of DMP suggests that pupils' decision-making ability can be optimally promoted and expanded through peer learning in the classroom.