In this study, secondary school students’ (N=617; grades 7 to 10) understanding of models and modeling was assessed using tasks which explicitly refer to the scientific disciplines of biology, chemistry, and physics and, as a control, to no scientific discipline. The students’ responses are interpreted as their biology-, chemistry-, and physics-related or general understanding of models and modeling. A subpopulation (N=115; one class per grade) was subsequently asked which models they had in mind when answering the tasks referring to biology, chemistry, and physics (open-ended questions). The findings show significant differences between students’ biology-, chemistry-, and physics-related understandings of models and modeling. Based on a theoretical framework, the biology-related understanding can be seen as less elaborated than the physics- and chemistry-related understandings. The students’ general understanding of models and modeling is located between the biology- and the p …show morehysics-related understandings. Answers to the open-ended questions indicate that students primarily think about scale and functional models in the context of biology tasks. In contrast, more abstract models (e.g., analogical models, diagrams) were mentioned in relation to chemistry and physics tasks. In sum, the findings suggest that models may be used in a rather descriptive way in biology classes but in a predictive way in chemistry and physics classes. This may explain discipline-specific understandings of models and modeling. Only small differences were found in students’ understanding of models and modeling between the different grade levels 7/8 and 9/10.