Based on the control-value theory, we investigated the achievement emotions experienced in science and mathematics classes by high school students in the context of digital technology use for educational purposes. Specifically, we examined the mediating role of cognitive appraisals of control and value in the relationship between students' digital technology use and emotions. Data were collected through online questionnaires from a sample of 1476 first- and second-grade high school students from 50 schools. The results of path analyses revealed that digital technology use (i.e. students' ICT-based activities related to learning) was positively associated with enjoyment and pride, both directly and indirectly through the perceived competence (control appraisal) and interest (value appraisal) in science and mathematics subjects. Findings further indicated that digital technology use was not directly negatively related to emotions of anxiety and boredom, but rather indirectly through students' cognitive appraisals. The perceived competence as control appraisal mediated the relation between digital technology use and both anxiety and boredom, while the perceived interest and importance as value appraisals mediated the effect of digital technology use on boredom only. The results can help educational practitioners to shape technology-based learning environments in affectively beneficial ways by utilizing learning technologies that enhance students' sense of competence and promote interest and value in mathematics and science subjects.