In recent years, students have shown growing interest in mobile learning and the use of mobile devices for learning English as a foreign language (EFL). However, it appears that further research needs to be undertaken to identify students' use of mobile devices and their attitudes towards them, especially in developing countries. To achieve this aim, three instruments, i.e. questionnaires (n = 345), in-depth semi-structured interviews (n = 128), and non-participant observations (50 sessions), were employed to collect quantitative and qualitative data. The results indicate that Iranian EFL students are generally positive about mobile learning and the use of mobile devices for learning EFL. The perceived benefits of mobile learning comprised opportunities for ubiquitous learning and access to the Internet, use of multimedia in the classroom, and portability. On the contrary, the findings suggest that students might be discouraged from the use of mobile devices due to several perceived impeding factors. The analysis of the data illustrated that Iranian EFL students mainly use mobile devices for non-academic purposes. The majority of students own smartphones and laptops and prefer to use tablet PCs, smartphones, and laptops for language learning. The findings of the observations suggest that even though some Iranian EFL teachers favor the use of mobile devices in the classroom, some of them prevent students from such use. In light of students' proposed strategies to implement mobile learning, the study suggests guidelines to integrate mobile learning in the EFL context of Iran and other similar contexts.