Much research on interest has taken place in the educational field of reading, raising questions about text-based interest. The study examines how discourse structures affect students’ interest in textbooks and focuses on three strategies: contextualisation, problem solving, and concrete elaboration. It used linguapragmatic methods to analyse text materials and describe linguistic structures of the strategies. A total of 386 eighth-grade students from Russian secondary schools took part in the experiment. The participants read passages from a textbook and rated them according to qualities on a scale. Rating scales measured a target quality (text interestingness) and predictor qualities (individual interest in the school subject, text novelty, text complexity, text comprehensibility, and text originality). To analyse their impact on interest, the correlation and regression models were calculated. It was found that participants’ reading interest depended on variations in the text stimuli. Originality and (stable) individual interests were the most prominent predictors of participants’ situational reading interest. The strategies increase text-based interest by presenting knowledge in original discursive ways. However, text-based predictors did not fully explain the variability in interestingness. The findings suggest that participants’ appraisals of text characteristics are not a comprehensive source of reading interest. The findings also provide an insight into the fact that the interest factor is beyond students’ genre expectations about textbooks. In light of the findings, the study benefits guidance for educational practitioners, textbook authors, and textbook editors. It delineates resources to enhance students’ interest in expository texts.