Knowledge sharing is a fundamental ability in industrial research and development centers through which employees can contribute to knowledge application, innovation, and ultimately the competitive advantage of the organization. Effective knowledge sharing among employees may considerably impact duration, cost and quality of research and development activities in such organizations. Therefore, this paper is aimed at examining the effects of motivational and organizational determinants in forming knowledge-sharing behavior in an industrial research and development center through synthesizing theory of planned behavior and social exchange theory. A descriptive-survey methodology was conducted and a questionnaire developed for data gathering. Partial Least Squares (PLS) method also used to test research hypotheses. Result of analyzing 85 questionnaires indicated that individuals’ attitudes toward knowledge sharing are positively affected by perceived enjoyment in helping others and perceived reputation enhancement, while negatively affected by perceived loss of knowledge power. It is also revealed that attitude toward knowledge sharing and subjective norms significantly determine intention to share knowledge, which then determines knowledge sharing behavior. In addition, research findings supported the positive effects of organizational climate and information and communication facilities as organizational determinants on subjective norms and perceived behavioral control, respectively. At last, based on research findings, some practical implications for knowledge management practitioners to foster knowledge sharing in industrial research and development centers suggested and research opportunities for future researchers to fill this research’s gaps proposed.