Researchers have highlighted the imperative need to perform studies on textbook use, given the acknowledged importance of textbooks as the primary teaching tool in foreign language classrooms and the roles of teachers in mediating the effects of textbooks on students' learning. Furthermore, past research considering Form-focused and Meaning-focused Instruction in textbook use is scant. Thus, the aim of this multiple case study is to provide a comprehensive account of patterns of textbook use in the previously non-researched context of Spanish classrooms, both regarding adaptation techniques and the presence of Form-focused and Meaning-focused Instruction arising from the application of such techniques and the retained original textbook activities. One English as a Foreign Language session in three different educational centers was observed (213 minutes in total). The adaptation techniques were identified and quantified with a coding scheme grounded in the data itself. Form-focused and Meaning-focused Instruction were measured with a scale purposefully designed for this study. Unlike previous research, several inter-rater reliability measures were adopted and the time devoted to each one of the classroom activities was measured. Results showed that the percentage of adapted activities was high, with a variety of techniques displayed, although such variety did not imply a radical lack of adherence to the textbooks' content. No statistically significant differences between the three teachers observed were detected concerning the percentage of the adapted activities, of their adaptation techniques and of Form-focused and Meaning-focused Instruction as resulting from their textbook implementation. Accordingly, the teachers' profiles appeared to correspond to "advanced" textbook transmitters. The comparison of Form-focused and Meaning-focused Instruction between the content of the three textbooks yielded non-statistically significant differences too. This study contributes to How to cite this paper: Criado, R. (2023). Patterns of Textbook Use in EFL: Adaptation Techniques and Their Effects on Form-Focused and Meaning-Focused Instruction.