The present study will investigate the effect of Task Based Language Teaching on accuracy , fluency and complexity of low and high proficiency level Iranian EFL learners. This quasi-experimental study uses two intact classes , one at each level of proficiency , there are 52learners in each proficiency level amp; all of them are male . A pretest is administrated to provide the researcher with the necessary information about the learner rsquo;s knowledge of speaking skills. After pretest the ...