Some previous research has illustrated teachers' conceptions and responsibilities in student-centered classes for assisting potent implementation of novel pedagogies. On the other hand, mobile learning has been widely adopted in education in the past decades, and a great deal of previous research has revealed the effects of mobile learning on students' learning. However, few studies have probed teachers' conceptions of mobile technology-integrated instruction. In this study, a total of 25 elementary school teachers in Taiwan were interviewed, and the phenomenographic method was adopted to explore the teachers' conceptions of mobile learning. As a result of the data analysis, seven qualitatively and hierarchically different categories (7-T) of mobile learning were revealed, namely a “Tool,” “Travel,” “Timeliness/Tutor,” a “Toy,” “Tracking,” “Teamwork,” and a “Tutee.” These hierarchical categories represent a spectrum ranging from “teacher-centered” to “student/teacher interaction,” and “student-centered” instructional strategies. Among the 7 categories, 4 (i.e., Toy, Tracking, Teamwork, and Tutee) are considered as student-centered instructional strategies, and the tracking category had the maximum frequency of teachers’ main conceptions of mobile learning. Thus, mobile technology offers opportunities to facilitate student-centered learning. The results provide educators and teachers with deep comprehension of advanced technology-enhanced learning for designing student-centered learning activities.