The expansion of technological applications such as computers and mobile phones in the past three decades has impacted our life from different perspectives. Language teaching is no exception and like other fields of study, language teaching has also influenced by new language teaching sources and software. More recently, there has been a passionate debate about the usefulness of the smart-phones for educational purposes and their possible uses in English language instruction; therefore, the present study investigated the impacts of interactivity perceptions on EFL learners' achievements in Online Mobile Language Learning (OMLL) course. To conduct the present study, 68 Iranian intermediate EFL learners were chosen among which 43 participated in Online Mobile Language Learning (OMLL) course and 25 others participated in conventional language classrooms. The results of the study demonstrated that OMLL has significant effects on learners' achievements; however, there are some challenges in conducting online mobile language learning (OMLL) courses in Iranian EFL context.