The purpose of this study was two fold – first, to involve teachers in the process of evaluating the EFL textbooks used in the Omani Basic Education schools and second, to develop a tool to be used by the teachers in the process of evaluation. The researcher formulated three research questions. (1) What are the relevant criteria for evaluating the Omani EFL textbooks used in Basic Education schools, (2) How far do the textbooks match the evaluative criteria?, and (3) Does the teachers' evaluation of textbooks vary according to gender and years of teaching experience? To answer the first question, the researcher developed a checklist including 43 questions to be used by teachers for evaluating the textbooks. For questions two and three, the analysis showed that the criteria matched the Omani EFL textbooks. It also revealed that there was no statistically significant difference between teachers' evaluation of textbooks in terms of gender and years of experience. The researcher recommended the Ministry of Education to evaluate the Basic Education textbooks and involve teachers in this process. He also recommended Colleges of Education to offer a course in evaluating the ELT materials.