Dynamic Assessment (DA), is grounded in Vygotsky's idea on Sociocultural Theory (SCT) of mind, his concept of Zone of Proximal Development (ZPD) and its related metaphor; scaffolding. This study examined the effects of dynamic assessment on improving reading comprehension of Iranian intermediate students who were learning English as a foreign language. The participants, a group of Iranian male intermediate EFL learners ranging in age from 17 to 20, were randomly assigned to two groups of 14. In this study, the experimental and control groups' performances on pretests and post-tests were compared through paired-samples and independent-samples t-tests. The treatment period lasted for 2 months (16 sessions). The results showed that the experimental group, which was instructed through DA, outperformed the control group which was instructed in a non-dynamic way.