The main purpose of this study was to understand the impact of organizational culture and knowledge sharing motivation on knowledge sharing. Therefore, a tool to measure knowledge sharing in the organization was developed. For achieving the above goal, 402 employees in five manufacturing companies in Taiwan were investigated. The returned valid questionnaires were 316. Hierarchical multiple regression was used to analyze the data, the main findings include that both the internal and external motivation of knowledge sharing were the most important factors that would influence on knowledge sharing. Besides, developmental culture and consensual culture in the organization also significantly affected knowledge sharing.