Mobile devices in the primary school classroom may improve literacy and numeracy learning, though concerns about risk of bias and uncertainty about modes of effect limit conclusions. This review gathered evidence on how mobile devices (including tablets, mobile phones, and handheld digital games) are used in primary school classrooms to help children's literacy and numeracy skills. An Expert Advisory Group supported the process to help findings relate to everyday practice. The review aimed to assess the impact of mobile devices in primary school classrooms on children's literacy and numeracy achievement, and its methodological quality. The secondary objectives were to assess whether some devices or classroom activities were more effective than others in supporting literacy and numeracy; whether some children benefitted more from these devices (e.g., across age or gender); and whether effects lasted beyond the duration of the studies.