Extensive reading (ER) has been well-documented as a robust tool for developing EFL students’ L2 skills. For a large portion of its existence, ER research and approaches have relied heavily on paper-based materials. However, appropriate paper-based graded readers for students are often limited at Japanese universities. Thus, this research project aimed at supplying 50 Japanese EFL students with access to a digital library, allowing them to use any device for reading eBooks that aligned with their reading interests and abilities. Through a mixed-methods approach, the participants of this study were surveyed about their attitudes toward graded readers via an online extensive reading digital library utilizing a modified version of Yamashita’s (2007) Reading Attitudes Survey and an open-ended questionnaire in order to get a better understanding of how cognitive, affective, and behavioral factors play a role in extensive reading mediated by technology.