Discussion surrounding the inclusion of mobile devices in K-12 classrooms has escalated since the early 2000s, and the literature base dedicated to mobile devices, mobile-learning, and e-learning has likewise grown. The majority of the research related to mobile devices and their inclusion in educational settings has largely revolved around efficacy and mobile-learning management systems. Additionally, several large-scale surveys have been conducted to assess the perceptions of students, teachers, parents, and administrators concerning mobile devices in educational settings. Despite these efforts, relatively little is known about students' perceptions of how they would use mobile devices, if given the chance, and the realities surrounding their actual use when given the opportunity. This research surveyed 458 middle-school students regarding their perceptions of how they would use mobile devices, if given the opportunity, during school. Students were allowed to use mobile devices during a two-week engineering design unit and asked to report their actual use of mobile devices. Several gaps between perceptions of how mobile devices would be used and the actual use by students emerged. Students did not use mobile-devices as often as they planned and student use, or lack thereof, displayed a potential disconnect between ways mobile devices are being marketed for use in K-12 classrooms and the ways mobile devices will actually be used by students.