This study has devoted itself to examining the effect of using cloud-based collaborative writing on EFL students' writing quantity and quality. Twenty-one EFL students studying at Jubail College of Education, IAU University participated in the study. They were pretested in writing quantity and quality before the treatment then they practiced cloud-based collaborative writing for a whole semester before being posttested in both measures. Results from non-parametric Wilcoxon Signed Ranks revealed no significant difference between the pretest and the posttest regarding writing quantity whereas it revealed a significant difference with regard to writing quality. It was concluded that cloud-based collaborative writing can be used to improve the quality of essays written by EFL students. Recommendations and research suggestions were introduced.