Cyberspace has created a new world for students to explore and learn. Teachers and families encourage students to use cyberspace for learning, but not all contents on cyberspace are suited for students. The online data provides countless benefits to users; however, it comes with serious threats as well. The present research aims to study cyber harm qualitatively among lower secondary school students in Arak City. To achieve this goal, a qualitative method was adopted. The data was collected through semi-structured interviews and data analysis was conducted using thematic analysis. Using a purposive sampling method and based on theoretical saturation criteria, 14 students of the lower secondary school in Arak were interviewed. The collected data were coded and analyzed based on 2 macro themes and 8 organizing themes. The results suggest that six categories of family harm, academic harm, social harm, psychological harm, religious harm and physical harm can be deemed as cyber harms among students. Two categories of the family (broken and troubled family and mismanagement and supervision) and social issues (poor media literacy, normative pressures and leisure time) were proposed as the chief underlying reasons for cyber harms. Finally, it should be noted that cyberspace has become an inseparable part of student's lives, and a greater presence in this space without sufficient media literacy in the absence of attractive real-life spaces such as family and school can inflict irreparable effects on students.