The Potsdam Textbook Corpus (PoTeC) is a naturalistic eye-tracking-while-reading corpus containing data from 75 participants reading 12 scientific texts. PoTeC is the first naturalistic eye-tracking-while-reading corpus that contains eye-movements from domain experts as well as novices in a within-participant manipulation: It is based on a 2 \(\times \) 2 \(\times \) 2 fully crossed factorial design, which includes the participants’ level of studies and the participants’ discipline of studies as between-subjects factors and the text domain as a within-subjects factor. The participants’ reading comprehension was assessed by a series of text comprehension questions and their domain knowledge was tested by text-independent background questions for each of the texts. The materials are annotated for a variety of linguistic features at different levels. We envision PoTeC to be used for a wide range of studies including but not limited to analyses of expert and non-expert reading strategies. The corpus and all the accompanying data at all stages of the preprocessing pipeline and all code used to preprocess the data is made available via GitHub: https://github.com/DiLi-Lab/PoTeC and OSF: https://osf.io/dn5hp/. The data is furthermore integrated into the open-source package pymovements, which can be used in Python and R: https://github.com/aeye-lab/pymovements.