Restrictive school phone policies are expected to positively influence adolescent in-school phone use and improve pupil wellbeing. However, there is a lack of research that explains how school phone policies impact on phone use and wellbeing. This qualitative comparative case study aimed to provide such explanatory data. Data were collected from 40 focus group interviews in 7 case study secondary schools in England (4 with permissive phone policies; 3 with restrictive phone policies), with 177 p