Given that interaction patterns are one of the most critical components of the collaborative writing (CW) strategy, especially regarding text quality, the present study investigates the interaction patterns of argumentative text quality in CW at advanced-level undergraduate L2 writing. Ninety-five undergraduate learners participated in the research and formed 37 groups. They were asked to write one collaborative task and record their CW sessions. The data in the present study were collected from students' recordings, written work, and the researchers' field notes. The study used Toulmin's Argumentative writing rubric (AWR) to evaluate the participants' written work regarding argumentative elements. The interactional patterns of the students were coded based on the framework. This framework includes interactional patterns like eliciting, greeting, justifying, requesting, questioning, or acknowledging. As a next step, we formed four interactional groups based on interactional patterns, and their written production was coded using Toulmin's model. The findings indicated a close relationship between interaction patterns and the quality of argumentation.