This study involved a group of 61 teachers in Ontario, Canada, who participated in a case study about classroom assessment practices. The participants were part of a district one-to-one technology programme that provided an iPad to each student and teacher in all Grade 7 to 9 classrooms. As part of the programme and its evaluation, teachers who were using the iPads were invited to participate in a case study focused on classroom assessment with the iPads. The case study consisted of 8 weeks of online activity (e.g., reviewing resources, discussing assessment practices, sharing instruments) and two face-to-face sessions with additional activities (e.g., examining exemplars, group discussion, reflection). In this study the researchers use self-reported data collected from teacher participants online and in-person sessions to investigate the use of iPads in classroom assessment. This article explores the dynamics of assessing Grade 7-9 students who are using personal iPads. In particular, we look at how formative assessment practices are shaped by the use of personal iPads. The findings provide insights into how iPads are used for formative assessment. Finally, we identify future considerations and implications for formative assessment practices that use personal portable devices such as iPads.