The present study explores the impact of smartphone use on course comprehension and the psychological well-being of students during class. Students in four classes (N = 106) were assigned to either a control group or quasi-experimental group. Students in the quasi-experimental group were instructed to place their smartphones on the front desk upon entering the class, while the control group had no instructions regarding smartphone use. Students filled out a brief survey about their course comprehension and psychological state (anxiety and mindfulness) during class. Results indicated that students whose smartphones were physically removed during class had higher levels of course comprehension, lower levels of anxiety, and higher levels of mindfulness than the control group. This study gives a comprehensive picture of the impact of smartphone use on students' psychological well-being in the classroom. The findings can aide educators in curriculum design that reduces technology use in order to improve the student learning experience.