Today we are seeing the rapid changes and complexity intensity of environment. In such conditions, creating competitive advantages requires the new kind of organizations that can create and manage knowledge. Sharing knowledge causes competitive advantages by reducing the costs and increasing the quality. Considering this fact that the knowledge sharing system success depends on what it is accepted and used by knowledge workers, thus it is important to identify the factors influencing knowledge sharing acceptance from knowledge workers perspective. So, in this research, the effect of managerial, technical and human factors on knowledge sharing information systems acceptance has been assessed by a structural model. A questionnaire was set in 34 question to conduct field studies on selected factors, which was confirmed by experts. Then it was distributed to collect data among knowledge workers in Tehran organizations that had implemented knowledge sharing system. The collected data was analyzed by correlation test, Freidman test and path analysis. The path analysis showed that effort expectancy, performance expectancy,  senior management support, motivation, staff involvement, training and social influence have positive and direct effect on intension to use system and intension to use system also has direct and positive effect on real use of system. Facilitating condition has direct and positive effect on real use of system. Friedman test indicated that the effective factors in order of priority and importance are: performance expectancy, effort expectancy, training, social influence, staff involvement, senior management support and motivation.