This study investigated the continuous influence of applying formative assessment on EFL (English as a foreign language) learners' anxiety and listening efficacy. The participants, divided into an experimental and a control group, were 60 Iranian EFL learners in an English-language institute. This study thus highlights the pedagogical implications of assessment in EFL classrooms. Therefore, this report investigated the effect of formative testing used by teachers on students' achievement in EFL classes and its effect on reducing anxiety and improvement of listening efficacy. All in all, our hypothesis was that providing learners with formative testing during the instruction will have a beneficial impact on their improvement and learning. The sample consisted of one experimental and one control group. The data collected were analyzed by using t-test. The results revealed that there was a significant difference in the level of achievement of the treatment group in the intended matters (anxiety and listening efficacy in comparison to the control group in the summative test due to taking advantage of formative assessment).