The usage of digital devices has been an interest in the field of education as one of the useful instructional methods for students’ better learning. Although the usage seemed to be related to their academic performance (e.g., Pekto et al., 2017; Skryabin et al., 2015), it was still unclear if the usage itself directly affected better academic results. Therefore, this dissertation explored an interrelationship between students’ usage of digital devices and academic performance with a mediation effect of their attitude toward using digital devices. The study analyzed the datasets of five Nordic countries collected from PISA 2018 and TIMSS 2019, where digital devices have been integrated into a part of their educational curricula (Godhe, 2019). A multilevel mediation analysis in the context of multilevel structural equation modeling with demographic control variables was applied to reflect the hierarchical structure of international assessments (i.e., students clustered into schools). The analysis figured out several findings. First, students’ frequent usage of digital devices was associated with their interest in using digital devices (i.e., ICT Interest) and willingness to use them actively to solve problems (i.e., ICT Autonomy), influencing their performances on the two international assessments. Second, there were differences among the variables of interest, depending on their demographic information. Finally, the direction of interrelationship tended to show different patterns across PISA 2018 and TIMSS 2019. Based on the findings, this dissertation expects to contribute to future educational policies regarding the integration of digital devices into education. For example, it would be necessary to find ways to improve students’ interest or autonomous behaviors when they are involved in activities that accompany digital devices.