This pilot study was designed to explore EFL teachers' and students' online interaction during wiki based collaborative writing activities. It aims to explore the collaborative behaviours that students engaged in and to what extent the teachers' intervention can promote students' collaboration. The study has a multiple qualitative case study design. Two EFL teachers and 18 of their secondary school students (aged 17-18 years) from a summer camp in Kuwait participated in a five-week-study. Data was collected from multiple resources, such as the wiki discussion page and history logs, and then triangulated with the teachers' and students' interviews. Variations were observed between the two teachers in terms of how they intervened in the students' online interactions at the organisational, socio-cognitive and socio-affective levels. At the wider levels, it appeared that the traditional classroom teaching and learning practices shaped the way in which the teachers interacted in the wiki. These practices seemed to influence the way in which the students collaborated together via the threaded mode and text mode. Some teachers' practices seemed to promote students' collaboration while others hindered it in various ways. It can be concluded that the mere presence of teachers can promote students' participation but does not necessarily assist collaboration. [For full proceedings, see ED565087.]