In digital world with spread of use of information and communication technology, online activities are the important part of daily adolescents’ activities and their protection from harms is a serious challenge for parents. The aim of this study is to qualitative investigation of mothers' protection strategies for control and management of adolescents’ online activities. Qualitative method was used to conduct the study and data were collected by using purposeful sampling and semi-structured interviews. The sample of this study was 10 efficient mothers. The data were analyzed by using grounded theory method (Strauss and Corbin approach). Findings showed that mothers with high level of cyber literacy who have regular online activities, and conduct thoughts and behaviors of their children with informing and ruling, have more positive effectiveness in protection. Indeed, according to mothers' reports, management of parent-adolescent relationship, peer relations, and entertainment have a role in reduction on harms.
