This study investigates the effectiveness of explicit and implicit written corrective feedback on increasing the correct use of prepositions. To this end, sixty Iranian pre-intermediate EFL learners were randomly assigned to two experimental groups, receiving explicit and implicit feedback, respectively, and one control group receiving no feedback. Each group included twenty participants. The homogeneity test of KET preceded the treatment. Prior to the treatment, a pre-test was administered to gain insight into the participants’ current command of English prepositions. After the treatment, the same set of tests was administered as post-test to assess the probable increase in the correct use of prepositions for the experimental groups compared to the control group. Analysis of the results through a one-way ANOVA revealed that the experimental groups who received explicit and implicit corrective feedback significantly outperformed the control group in terms of the correct use of prepositions. The comparison of the experimental groups reported no statistically significant relationship. The results of this study indicate that language learners benefit from teacher-provided feedback in improving their grammatical accuracy in writing. Furthermore, more research is merited as there is a lot to investigate in this field.