Tacit knowledge of startup entrepreneurs is sharable and will improve in a mutual process of co-learning and sharing. This process plays the key role in launching a new business, but it is happen seldom among startup entrepreneurs’ because they are so sensitivity to their startups ideas. As the research goal is to identify factors affecting knowledge sharing among startup entrepreneurs’, we have selected a methodology of narrative cased study. In this qualitative research in order to collect information, we have conducted a deep semi-structured interviews with 18 knowledge aspirants’ startup entrepreneurs (11 male and 7 female; including 13 IT startups and 5 other services entrepreneurs). Coding, categorizing, and analyzing verbal evidences of startup entrepreneurs’ interviews, has been conducted by ATLAS.ti. Software. Research findings showed in an integrated design of triplet factors affecting sharing knowledge among startup entrepreneurs; (1) individual factors (including personal beliefs and motives, connecting with social networks, interpersonal communication skills, trust, fear of sharing, awareness of knowledge sources, and family), (2) Organizational factors (leadership style, strategy, technology, motivation and reward system, organizational rules, culture and structure) and (3) environmental factors (industry national environment, business national environment, industry international environment and business specific environment such as customers and competitors relations.
