This study aimed to identify the perceptions of preparatory school students studying in the School of Foreign Languages in a state university towards using Edmodo to improve their writing skill in English. The participants were 52 students who used Edmodo together with Google Docs collaboratively and interactively for their nine collaborative and individual writing tasks. Besides, the teacher has uploaded some course materials onto Edmodo to support their learning process. The students have studied various EFL writing tasks for one semester through Edmodo. In order to collect the data, convergent parallel design of mixed design was adopted. Quantitative and qualitative data were collected and analysed separately, then they were classified and interpreted together. The results revealed that the participants highly favoured using Edmodo for their writing classes and found it very useful and enjoyable, and they also pointed out that using Edmodo interactively helped them develop their writing skill. In addition, they highly appreciated the e-portfolio function of Edmodo since it has provided easy access to their previous tasks and related feedback.