The effect of assessment types (self, peer, and teacher) on the EFL writing strategies development was examined in this study. Sixty upper-intermediate EFL learners at Qazvin Islamic university in four groups (one control and three experimental groups) were studied. One-way ANOVA checked homogeneity of the groups prior to the treatments and, then, the participants’ records and diaries were employed to gather data. Explanatory and descriptive analyses were implemented to analyze and classify the strategies the EFL learners picked up. This provided the type, frequency, and percentage of the strategies the participants mostly employed. The results revealed that the experimental groups, namely, self-assessment group, peer assessment group, and teacher assessment group employed more cognitive and meta-cognitive strategies than the control group. Affective strategies were more appealing to the control group. Focusing on the diction of the words, concentrating on the complex structures used by different writers, and making use of the structures the participants became interested in or found suitable were the most frequently referred to strategies. Teaching strategies the participants more picked up in this study might enhance EFL learners’ writing development at TEFL centers.
