This study investigated the impact of using the technique of self-monitoring on non-academic EFL learners’ composition writing. Fifty female students studying English at Navid English Institute in Shiraz, Iran were chosen based on the results of a proficiency test. They were all 16-20 years old and were intermediate learners of English who were divided into two control and experimental groups and took a writing pre-test. The experimental group (EG) received a training program on the effective use of the technique of self-monitoring proposed by Charles (1990). That is, they learned to add annotations expressing doubts and queries on various parts of their five composition drafts. The students in CG wrote their drafts without annotations. At the end of the twenty-second session course, both groups took a writing posttest. The results indicated that the learners in EG performed significantly better and the global features of organization and content in their writing were enhanced. Surveying the students’ views on self-monitoring, through a questionnaire, revealed their interest in taking charge of their writing task. Findings point to the efficacy of the self-monitoring technique in promoting learners’ writing proficiency and autonomy in handling writing tasks.