This study aimed to develop instruments to evaluate teaching performance of social studies teachers in Adhahera Governorate. Descriptive methodology has been used in analyzing the previous studies relevant to evaluating teacher's performance. Thus, teaching competencies were derived to evaluate the efficiency of social studies teachers. To achieve the study's aims, two scales were developed: the first scale was to evaluate teacher's performance by the principals and senior teachers. It consisted of four dimensions; each was measured by a number of items with a total of 31 items. The second scale purported to evaluate teacher's performance by the students. The scale consisted of thirty five items measuring seven dimensions. Reliability and validity of the instruments were verified with a pilot sample of students (n=145) & sample of principals and senior teachers (n=11). The analysis of the data showed the two scales possessed adequate validity and reliability estimates. Tools were applied to the study sample which consisted of students (n=719) and principals and senior teachers (n=48), who evaluated (n=145) teachers in Adhahera Governorate in the Sultanate of Oman. Confirmatory factor analysis (CFA) confirmed four factors for the principal's instrument and seven factors for the student's instrument. The study concludes that the instruments possess good psychometric properties and can be utilized for evaluation and research purposes.