Textbooks are the significant means of communication and delivery of factual knowledge between writers and learners in the academic world. Text organization and discourse persuasion are essential concepts in academic contexts where the writers have to consider the academic audiences and their educational needs. So, Interactive metadiscourse signals, which refer to text organization markers, provide useful information about how writers support their arguments, and interactional metadiscourse signals which build up a relationship with readers in different contexts are crucial components in textbooks. This study explored the use of Interactive and Interactional metadiscourse signals across four disciplines: Applied Linguistics, Sociology, Computer Science, and Economics in textbook chapter introductions.The analysis of this study showed that the distribution of Interactive metadiscourse signals was higher than Interactional metadiscourse signals in textbook chapter introductions. The findings of this study may have some pedagogical implications for teaching writing in academic disciplines to EFL learners.