The emergence of mobile technology and different social networks (SNs) can greatly influence the area of language learning. This is especially true for productive language skills, i.e. writing and speaking. Therefore, this study highlights the effects of using WhatsApp on EFL young learners’ speaking skill. Another focus of the study is to explore how EFL students perceive using WhatsApp as a language learning tool before and after using it. To achieve these aims, 45 young female Persian speaking lower-intermediate learners of English in Iran Language Institute (ILI), Dezful, Iran, were selected as the participants of the study based on their OPT (2007) scores. They aged from 12 to 14 forming two homogeneous groups (control and experimental). The data were collected from the participants by means of speaking part of KET and a questionnaire (seeking their perception of language learning through WhatsApp before and after the treatment). The findings of the pre-test questionnaire revealed the learners’ positive attitudes toward the importance and use of WhatsApp before the treatment. As the treatment, the teacher gave some weekly topics to the participants in the experimental group in order to talk about in the WhatsApp group and in the classroom. The treatment lasted for 10 weeks. Paired-samples t-test was administered to compare the obtained data of pre-test questionnaire and post-test questionnaire. The results indicated that the experimental group had a significantly higher perception toward using WhatsApp as a learning tool. In addition, using WhatsApp showed to be effective in enhancing EFL students’ speaking skill. It provided them with the chance to exchange ideas and discuss different topics; therefore, it led to the improvement in their speaking skill. It can be concluded that WhatsApp can be used as a new tool in English language teaching and learning; both teachers and learners can benefit from the appropriate implementation of WhatsApp in language pedagogy
