The instant messaging application WhatsApp enables quick, interactive multimedia communication in closed groups, as well as one-on-one interactions between selected group members. It has become one of the most popular applications, and is regularly used by both teachers and students for personal and group communication. In the present study, we explore student perspectives on the phenomenon of WhatsApp ״classroom groups״ ,in which both teachers and students from a particular classroom interact with one another in closed groups. Our methodology combines interviews and focus groups with students aged 13-18 (N = 88). The findings reveal that WhatsApp has become a central channel of communication among Israeli school communities, and is used for organizational purposes (sending and receiving updates and managing learning), as well as a means for teachers to enforce discipline. Students view favorably many of WhatsApp׳s characteristics: Easy access, its communal nature, privacy boundaries (low exposure to personal profile information), the written, mediated communication format, and the simplicity and ease of switching from group to one-onone communication formats. Students also recognized limitations, specifically the potential of communication overload, and challenged existing teacher beliefs concerning their ability to monitor and affect student interactions in social media. Finally, we report on the central role of parallel ״sans-teacher״ WhatsApp classroom groups, as ״back stage״ discourse arenas that accompany the ״front stage״ activities in class and in the ״official״ classroom WhatsApp group.