The current study examined the modification devices (MDs) used by non-native speakers (NNSs) learning EFL during dyadic task-based interactions. Three meaning-oriented tasks, namely picture-description, spot-the-difference, and opinion-exchange, were used to elicit data from 24(12 male and 12 female, forming 4 male-male, 4 female-female, and 4 male-female dyads) Iranian EFL learners with intermediate language proficiency. All interactions were video-taped and transcribed. For the sake of systematicity, only the first 150 sentences of transcribed data were analyzed to assess the relationship among interlocutor type and the usage of different types of modification devices. The findings revealed that ‘confirmation check’ was the device mostly used by both genders. The results also demonstrated that ‘clarification check’ was the most frequently used strategy for negotiation among the students. Data from this study propose that these modification devices facilitate comprehension of input and output and enhance the negotiation for both meaning and form. Further results and implications are discussed in the paper.