This study reports on the investigation of the effect of mobile assisted learning environment on academic achievement, acceptance of mobile learning tools and cognitive load of EFL students. This study used a mixed methods approach which involves the collection and analysis of quantitative and qualitative data to identify the effect of mobile learning in a foreign language learning environment. Quantitative data were collected from 63 foreign language learners via an academic achievement test, cognitive load scale and mobile learning tools acceptance scale, before and after a six-week intervention period. Following the intervention, eight students from the experimental group answered open-ended questions about their experience during group interviews. Results showed a significant difference in academic achievement and mobile learning tools acceptance level of students in favor of the experimental group. The study also showed that although the students learning a foreign language in mobile assisted learning environment were not cognitively overloaded, students in the control group were. The themes emerged from the qualitative data point to the positive and negative sides of the mobile-assisted learning environment.