This study aims to reveal to what extent the activities for critical thinking skills in "My Beautiful Language" book for grade eight basic education are available from the viewpoint of the teachers in the Sultanate of Oman. To this end, the candidate developed a questionnaire of (22) critical thinking skills appropriate for the students of grade eight basic education distributed into four main skills, namely induction, deduction, reasoning, and assessment. The study uses the descriptive approach. The sample of the study comprises (828) activities in "My Beautiful Language" book for grade eight basic education for the academic year 2018/2019 CE, demo version. The study analyzes the activities in light of the four critical thinking skills: induction, deduction, reasoning, and assessment. The most important results of the study: - Reasoning is the most prevalent skill in the activities at (3.85%) followed by assessment (3.62%), induction (3.57%) and then deduction (3.41%). - There are no statistically significant differences at the significance level (0.05) in the level of critical thinking skills (induction, deduction, reasoning, and assessment) attributable to social gender and years of experience variables. - There are statistically significant differences at the significance level (0.05) in the level of critical thinking skills (induction and deduction) in favor of the teachers who hold bachelor degree attributable to their degree variable.