English coursebooks used in vocational secondary schools should accommodate the engineering students’ needs for their future profession. It is essential to reveal company trainers’ and engineers’ perception of the English coursebook used at school to know whether the English coursebook meets students’ needs for their future profession or not. Therefore, in this study, we investigated company trainers’ and engineers’ perception of the English coursebook that is used at vocational secondary schools based on the social semiotic perspective. We distributed open-ended questionnaires and conducted in-depth interviews to both engineers and engineering company trainers as professionals about the topics and registers provided in the English coursebook. The results of data analysis revealed that the topics and registers in the coursebook are not relevant with what students need for their future profession as engineers. In fact, both engineers and company trainers believed that the English coursebook should provide topics and registers related to the engineering field. Thus, we hope that the findings of this article would positively contribute to the development of English materials and coursebooks for vocational secondary school level. پرونده مقاله