The current study aimed to explore middle school mathematics teachers&rsquo / use of mathematics textbooks and examine their integration of tasks in the textbooks into teaching. The framework of a mixed methods research design guided data collection in this study. A questionnaire called the Use of Mathematics Textbooks Questionnaire was developed and validated to identify the ways teachers benefit from textbooks. The factor analysis revealed four dimensions, namely Reading Student Edition Textbook, Selecting Questions from Workbook, Reading Teacher Edition Textbook, and Selecting Tasks and Problems from Auxilary Books. The results of the study showed that teachers used the student edition textbook for mostly during class and for lesson preparation. Teachers also used the student edition textbook for explaining the topic and the introductory tasks. However, they rarely used it for selecting problems and examples. Teachers read the student edition textbook mostly during and prior to class / and mostly use it for topic explanation, but rarely for problems and examples. They stated that they frequently selected questions from the workbook that were not included in the textbook. However, they occasionally picked questions to use during lessons. They frequently used auxilary books to select questions similar to the ones in the high school entrance exam problems. In examining the process of teachers&rsquo / use of mathematics textbooks, it was argued that there were interpretive processes as teachers engage with and use textbooks. The analysis of interviews and observations showed that teachers read textbooks and select tasks and questions from those books. In their decisions about using tasks from textooks, teachers usually considered the nature of tasks and students&rsquo / characteristics.