The main goal of many students of English as a foreign language (EFL) is to be fluent in the target language, i.e. to be capable to transfer their thoughts smoothly and easily in different contexts. The present study examines the effect of pedagogic intervention on enhancing speech fluency in EFL using a pretest – immediate posttest – delayed posttest design. Two groups of 32 EFL students at a University in Iran took part in the study, receiving the same amount of instruction (18 hours over 18 weeks). The Control group listened to / viewed authentic audio recordings and movies in English, discussed their contents, and completed a variety of speaking skills tasks but received no fluency training. The Experimental group spent part of the time on fluency strategy training, encouraging the memorization, repetition, and retelling of the audio and video materials. Systematic interviews were run to assess the EFL learners’ speech fluency. The findings revealed that the fluency training significantly enhanced the EFL students’ speech fluency. The findings also show that students’ second language speech fluency development can be partly predicted by the fluency in their first language. These results have pedagogical implications for practitioners in EFL settings, material designers, and EFL instructors.