The first-year secondary school students' level of acquisition of geographical map skills was generally low. This resulted from the students' dependence on the teachers. In addition, the teachers used traditional methods but none of the modern ones. The purpose of this study was to investigate the effect of using Keller Plan and the prior achievement level on the first-year secondary school students' acquisition of some geographical map skills. More specifically, the study sought to answer the following major question and its sub questions: 1. What is the effect of using Keller Plan on the first secondary school students' acquisition of the skills of reading the map symbols and measuring distances on the map? a. What is the effect of using Keller Plan as a teaching method compared with that of the traditional method on the first secondary school students' acquisition of the skill of reading a geographical map? b. What is the effect of using Keller Plan as a presentation technique compared with that of the traditional method on the first secondary school students' acquisition of the skills of measuring distance and area on a geographical map? c. What is the effect of the prior achievement level of the first-year secondary school students on their acquisition of the skill of reading a geographical map? d. What is the effect of the prior achievement level of the first-year secondary school students on their acquisition of the skills of measuring distance and area on a geographical map? e. Is there an effect for the interaction between the method of teaching and the prior achievement level on the first- secondary. school students' acquisition of the skills of reading the map symbols measuring distances on a geographical map? f. Is there an effect for the interaction between the method of teaching and the prior achievement level of the first- secondary school students' acquisition of the skills of measuring distances and area on a geographical map? The study was undertaken on a sample of (124) students representing (4.4%) of all the first-secondary public school students in the Dakhlia Region in the Sultanate of Oman in the academic year 1998-1999. These students were in four classes in two schools; two classes in each school. The (62) students in the experimental group were taught by the means of Keller Plan. The (62) students in the control group were taught by the means of the traditional method. The instruments of the study used to answer its questions were: (1) planning lessons on the use of map symbols and the measurement of distance and area on a geographical map according to Keller Plan. (2) constructing two tests to measure the effect of the teaching strategy according to Keller Plan. A panel of experts established the validity of the instruments. The researcher made the necessary changes and modifications suggested by the experts. The researcher calculated the reliability co-efficients for the two tests by using the Keuder-Richardson- Formula #20. The co-efficients were (0.80) for the test of the skill of reading the symbols of a geographical map and (0.82) for the test of the skills of measuring distances and area on a geographical map? The researcher used several statistical techniques to analyze the data of this study. These techniques were the means, two-way ANOVA, Two-way ANCOVA, and the Sheffe post-hoc test. The results of the study showed that: 1. There were statistically significant differences between the experimental and the control groups in favor of the experimental group based on instruction via the Keller Plan. 2. There were statistically significant differences between the experimental and the control groups in favor of the experimental group which was attributed to the prior achievement level. 3. There were no statistically significant differences between the experimental and the control groups based on the interaction effects between the teaching method used and the prior achievement level. Based on the findings of the study, the researcher made the following recommendations: 1. There is a need for the adoption of modern instructional strategies which are suitable for the teachers' skills and interests. 2. In-service training workshops must be organized in order to train teachers on the use of modern instructional strategies. 3. The social studies school textbooks should be conducive to individualized instruction and at the same time should be appropriate for the Omani public schools.