This study aimed at developing EFL students' writing skills, by examining the effect of teacher intervention in online collaborative writing on students' writing performance, reading comprehension, and learner autonomy. The study sample comprised 98 fresh female students enrolled at the College of Education, Kuwait University, who were of different majors. The students were divided into three groups; two experimental groups and a control one. Both treatment groups were engaged in online collaborative writing projects, utilizing google documents (GD) program. However, the first group was exposed to high teacher presence intervention (HTP), whereas the second group was exposed to low teacher presence intervention (LTP). The treatment spanned over a period of 13 weeks. The tools incorporated in the study included a writing test, a reading comprehension test, and a learner autonomy questionnaire. Results showed that both groups improved in writing, reading comprehension and leaner autonomy, compared to the control group. Nonetheless, the (HTP) outperformed the (LTP) in most writing skills. As far as reading comprehension and learner autonomy are concerned, no differences could be detected between both treatment groups. The study sustained the conclusion that high teacher presence in online contexts is paramount in improving students' writing skills, especially for those whose language proficiency is not very high. It was suggested that teacher high presence facilitated students' interaction, collaboration and reciprocal learning process, without undermining their autonomy.