This study aimed to investigate EFL students' metastrategies in learning English writing. The participants were 34 undergraduate non-English major students taking a paragraph writing course at a university in southern Thailand during the semester 2/2017. Text analysis method was employed. Students' self-reflection at the end of the course was analyzed to examine their metastrategies in cognitive, social, affective, and motivational domains in four phases of learning, namely, forethought, performance, self-reflection, and beyond-class. The uses of each student's metastrategies were quantified and the content of the metastrategies was categorized and reported interpretively. The findings revealed that the students were likely to deploy a wide range of metastrategies when learning writing. Cognition was found to be the most frequently used domain in all phases of task. This study suggests the students tended to be strategic learners and their self-regulatory learning tendency is likely to be influenced by the class environment where they were required to engage in cooperative learning provided with some freedom in their learning.