As a primary source of input for language learning, textbooks provide learners with various language samples. This paper investigates whether Korean English textbooks provide an adequate language model to follow, particularly focusing on how an invitation is tendered and responded to. Dialogues that contain an invitation were pulled from seven high school English textbooks and analyzed from a Conversation Analytic (CA) perspective. According to the results of analysis, textbook dialogues generally do not follow how an invitation sequence is organized in authentic English conversation as manifested by the inadequate or lacking presentation of a preinvitation, and contain invitation practices that are not yet known to occur in English conversation. It was also found that an invitation is frequently portrayed as incidentally tendered due to its occurrence with certain turn components. Lastly, textbook dialogues provide a limited variety of input as shown by the lack of insert expansion instances and the limited presentation of responses in form and position. This researchsuggests the need to incorporate our knowledge of how conversation works into scripting dialogues for English learners. (177)