Second language (L2) writing research has shown that L2 learners routinely scaffold each other when working together to co-construct written texts. The analysis of peer interaction has focused largely on the occurrence of languagerelated episodes (LREs), with fewer studies documenting how learners discuss other elements of written texts, such as their content or organization (Elola & Oskoz 2010; Storch 2005; Storch & Wigglesworth 2007; Wigglesworth & Storch 2009), or establishing a link between student interaction and text quality. This chapter describes the interaction that occurred when Thai EFL students worked in pairs to write summary and problem/solution paragraphs and explores whether their discussions were related to text quality in the form of analytic ratings. The results indicated that problem/solution collaborative writing tasks showed a positive relationship between student talk and text quality and elicited significantly more discussion of content, organization, and language than summary tasks. Implications are discussed in terms of pedagogical considerations for the use of collaborative writing tasks in EFL contexts.