Currently, 95% of American teenagers own a smartphone device, and smartphone users spend on average about 5.4 hours a day on them. Smartphone ownership, usage, and dependency are higher among teens and young adults than in any other age group. This study addressed a gap in research by examining high school teachers' perspectives on two topics: the impact of smartphone usage on students and classroom smartphone policies. It contributes to a deeper understanding of the social, psychological, and academic effects of smartphone use on students and of the impact of teachers' beliefs surrounding smartphones on the classroom policies they set regarding those devices. In addition, this study aimed to shed light on the need to create effective and equitable smartphone policies and practices to help promote a classroom environment conducive to learning. Survey data from 248 teachers from six high schools in the Southern California region of the United States of America produced results indicating that teachers who have stronger negative beliefs concerning the social, psychological and academic effects of smartphones on students typically set a stricter classroom smartphone policy. Implications include helping students regulate their smartphone usage so that these devices can be effective tools for learning, not a distraction. Based on the findings from this study, an increase in face-to-face social interactions among students is recommended to increase academic achievement and decrease problematic smartphone use.