Argumentation is a key skill in most school subjects and academic disciplines, including mathematics and science. It is possible that similarities and differences between how argumentation is expressed in different subjects can contribute to, or disrupt, students' transferrable argumentation skills. The purpose of this study is therefore to increase the understanding of such similarities and differences concerning the use of argumentation in mathematics and science texts. To reach this goal, the study compares argumentation with a focus on argumentation markers and argumentative structures in first-semester university textbooks in mathematics, chemistry, and biology. Results show that common linguistic argumentation markers in mathematics and science textbooks include for example "because," "if," "thus," "so," and "therefore" and that there is significantly more argumentation in the mathematics textbook compared to the science textbooks. Further, the results indicate differences in patterns of how argumentation is used, including for example that the mathematics textbook contains more complex argumentation compared with the chemistry textbook. Thereby, the subjectspecific languages in the disciplines have the potential to offer students different examples of argumentation.