The current study aimed to reveal the existence of a correlation between the level of application of the individual performance measurement system and institutional proficiency and the development of job performance for the employees of Muscat Municipality. The researcher used the questionnaire tool to collect data, where (204) questionnaires were retrieved, and the results of the analysis of outliers showed that there were (9) cases classified as outliers and outliers, and they were deleted, bringing the total number of the sample members participating in the answer to the study tool (195) participants from origin (204), Thus, the current study will depend on their answers in conducting statistical analyzes and answering the questions of the study, and the questionnaire consisted of two axes: the first axis: individual performance and institutional proficiency (15) paragraphs, and the second axis developing job performance (15) paragraphs, and its validity and stability were confirmed, as the coefficient reached Cronbach's alpha (0.947), arithmetic means, standard deviations, Pearson's correlation coefficient, and analysis of variance were used to answer the study questions. The results showed that there were no substantial differences of statistical significance between each of the axes of individual performance, institutional proficiency and job development due to gender, age or years of experience. The performance of the unit for the variable of individual performance and institutional proficiency, and the value of the relationship was (0.709), that is, the greater the linkage of productivity to incentives, the greater the comprehensiveness of the performance of the unit. Keywords: individual performance measurement system and institutional proficiency, performance development, Muscat municipality employees.