The article reported a case study investigating the scaffolding strategies of twelve Asian EFL learners in four small groups’ scaffolding strategies during two online collaborative writing (OCW) tasks in a composition course using Google Docs as a writing platform. Of interest was how EFL learners with different L1 scaffold each other while co-constructing OCW tasks, and also if scaffolding strategies used during OCW tasks influence writing performance. Data collection included pre-test and post-test writing, two OCW tasks on descriptive and argumentative essays, learners’ use of scaffolding and non-scaffolding negotiations during OCW tasks observed through Google Docs revision history, and student reflection. The findings showed that learners in small groups employed both scaffolding and non-scaffolding dialogues to jointly construct their OCW tasks by giving advice, providing suggestions, responding to questions or requests, asking questions, or clarifying ideas. Learners who contributed more texts directed their team and initiated both scaffolding negotiations and non-negotiations while performing group work. The study results also revealed that members who employed more scaffolding negotiations during their OCW processes likely produced a better quality of writing in their post-test. Nevertheless, these findings indicated that members in small groups benefited from both scaffolding and non-scaffolding negotiations as they helped in task revisions. The findings contributed to research that has investigated online scaffolding strategies in EFL learners’ collaborative writing tasks.