This study aimed to investigate the impact of different types of scaffolds on the writing regulatory skills of a cohort of Iranian learners of English (N = 120). The article reports a comparison of the pretest and posttest performance of learners in 4 experimental conditions--namely, the metacognitive scaffolds, conceptual scaffolds, procedural scaffolds, and strategic scaffolds conditions--in terms of their scores on a self-report questionnaire. We analyzed data using 2 one-way analyses of variance and 4 paired-samples t tests. The results indicated that written scaffolds in general statistically significantly improved the learners' perceptions of their ability to regulate their writing in another language process. On the whole, metacognitive written scaffolds proved more effective at increasing the learners' writing self-regulatory skills.