It is generally observed that the textbooks employed in the classrooms play a crucial role in the process of teaching and learning a second/foreign language. As a result, a number of studies have been carried out to evaluate English Language Teaching (ELT) materials. Trying to contribute to this growing body of literature, the present study was conducted to evaluate the eight most popular global textbooks which are taught in Iranian ELT institutes in terms of their task types according to Nunan's (1999) classification of the tasks.