The study objects at identify the factors affecting knowledge sharing and its role in improving the job performance of information specialists in Omani academic libraries based on the Theory of Reasoned Action (TRA), through achieving the following sub-objectives: Knowing the impact of personal factors on the behavioral intention of information specialists towards sharing knowledge, knowing the Organizational factors on the behavioral intention of information specialists towards sharing knowledge, knowing the effect of social factors on the behavioral intention of information specialists towards sharing knowledge, knowing the effect of the behavioral intention towards sharing knowledge on the job performance of information specialists .The study depends on the quantitative approach to achieve its objectives, and the questionnaire was used as a tool for data collection. The study found the following results: the presence of a statistically significant effect of the behavioral intention of information specialists towards knowledge sharing due to personal factors, the absence of a statistically significant effect of the behavioral intention of information specialists towards knowledge sharing due to the Organization factors, and the presence of a statistically significant effect of the behavioral intention of information specialists towards knowledge sharing due to social factors and there is a statistically significant effect of the behavioral intention variable of information specialists towards knowledge sharing on job performance . Based on the findings of the study, it recommends the following: Building a system of material and moral rewards that encourages and motivates employees to activate knowledge-sharing activities, The need for senior management to be aware of the importance of supporting employees and encouraging them to activate knowledge-sharing activities, and informing them of their role in improving job performance, The authors of the vision, mission, values and objectives of the institutions must clearly include knowledge-sharing activities and consolidate them in the institutional culture, The efforts of improving communication channels in organizations; To increase social interaction between employees, which in turn contributes directly to the exchange of knowledge, ideas and opinions.