Teaching grammar has always created some challenges for EFL teachers. Therefore, this study explored the effect of four scaffolding strategies as contextualizing, modeling, metacognitive scaffolding, and bridging on Iranian EFL students’ grammatical knowledge. Moreover, this study examined Iranian EFL learners’ attitudes towards scaffolding strategies. To fulfil the purpose of this study, 40 language learners were chosen based on convenience sampling as the participants of this study. They were both males and females between 20 to 30 years old divided into two groups as the control and experimental groups. After assuring the homogeneity of the students in terms of their English proficiency in general and grammatical knowledge in particular, a parallel achievement test was administered to both groups as the pre-test. Following that, as the treatment, scaffolding strategies were applied for the experimental group to teach grammar and a traditional way of teaching grammar for the control group. After running the classes, a parallel achievement test was administered to both control and experimental groups as the posttest. The data analysis revealed that the experimental group that received scaffolding strategies significantly outperformed in the grammar part compared to the control group which received a conventional way of teaching grammar. It is believed that utilizing scaffolding strategies can motivate learners and facilitate the tough task of grammar learning and thereby make teachers aware of their ability to obtain success in their teaching process.
