The aim of the study is to investigate the impact of reciprocal teaching on the development of critical thinking skills and the academic achievement among grade eleven female students in biology. The sample of the study consisted of (50 students) selected from the Governorate of Batinah South. This sample was divided into two groups: the experimental group (25 students), which was taught using the strategy of reciprocal teaching, and the control group, (25 students) which was taught using the conventional method. hieve the aim of the study, the researcher used Watson & Glaser's Scale of critical thinking skills. In addition, an achievement test in biology was designed. The validity of both instruments was checked by a panel of judges, where the reliability is found to be (0.92) for the critical thinking skills scale and (0.83) for the achievement test in biology using Pearson Correlation Coefficient. Therefore, the two instruments were on a high degree of stability. The researcher also designed a teacher's guide based on using the reciprocal teaching strategy for a unit in biology text book "Transport in Living Organisms." The result of the study showed that there were no significant differences at a = 0.05) between the average scores of the experimental and the control groups on the scale of critical thinking skills. Moreover, there was a significant difference at (a = 0.05) between the mean scores of the experimental group in the pre and p thinking scale in deduction skill in favor of post-test. Finally, there was a significant difference at (a= 0.05) between the mean scores of the experimental group and the control group in the post achievement test in the levels of understanding, application and the total score. Accordingly the researcher recommends that students should be trained on the ways of getting the information themselves through the use of books and the learning resource center, The researcher also suggested conducting new studies on the use of reciprocal teaching strategy in other educational stages and different education variables.