This study aimed at identifying the geographical concepts included in the geography textbook for Third Preparatory Grade, and the extent to which the students have acquired these concepts, in the Sultanate of Oman, through answering the following questions: 1/What are the geographical concepts included in the geography textbook for the Third Preparatory Grade? 2/To what extent do students of the Third Preparatory Grade (male/female)acquire the geographical concepts included in the textbook at the three first levels of the cognitive domain: (Knowledge ; Comprehension; Application)? 3/Is there any difference in the level of students' acquisition of these concepts that can be attributed to the variable of gender ( male, female)? 4/Is there any difference in the level of students' acquisition of these concepts that can be attributed to the variable of region (Dakhiliya , Muascat)? 5/What is the effect of the students previous level of achievement on the level of their acquisition of the geographical concepts included in the textbook? The study population consisted of all Third Preparatory Grade students (males/ females) in al-Dakhiliya and Muscat regions, of the academic year 2001/2 The study sample consisted of 803 students of the Third Preparatory Grade (410 males, 393 females). The researcher analyzed the geography textbook using the method of Content Analysis for determining the geographical concepts that are included in textbook. The researcher prepared a test comprised of 45 questions, on the concepts included in the textbook, covering the three levels of the cognitive domain: Knowledge;Comprehension; Application. Then the test was administered to the students, members of sample. In summary, the most significant results are as follows: 1- The distribution of the geographical concepts in the textbook was inconsistent to the assigned levels of:Knowledge; Comprehension; Application. The level of students , both male and female, acquisition of the geographical concepts at the cognitive levels of knowledge and comprehension came lower than the educationally accepted level. Male students acquisition of the geographical concepts at the knowledge and comprehension levels was lower than the educationally accepted level of (60%); The female students' acquisition of the geographical concepts was higher than the educationally accepted level of (60%); The level of students acquisition of the geographical concepts at the application level was higher than the educationally accepted level; There exist statistically significant differences at (0.05) level in the sample group acquisition of geographical concepts attributed to gender in favour of females. There exist statistically significant differences at (0.05) level in the sample group acquisition of geographical concepts attributed to region, in favour of Al-Dakhiliya, at the levels of comprehension and application. There exist statistically significant differences at (0.05) level in the sample group attributed to the level of achievement, in favour of students of high achievers. The study recommended 1. Highlighting the geographical concepts in the content and defining them clearly; Textbook activities should include questions based on the geographical concepts at the different levels of the cognitive domain: knowledge; comprehension; application