With the growth of information and communication technology (ICT), more organizations are focusing on the development of online business communities (OBC) to help facilitate better knowledge sharing (KS) activities. Since today’s business environment is dynamic, having up-to-date and ongoing knowledge is an advantage for organizations to be competitive. Ironically, having employees to share their knowledge virtually is one of the biggest challenges faced in OBC. Low level of contributions is caused by withholding of efforts (social loafing - SL) by the employees. SL is known for its negative impacts on group performance. Unfortunately this effect is under-researched in knowledge management (KM) literature and have largely been ignored by IS researchers. Therefore this study will try to examine what are the factors that contributed to SL from Expectancy and Social Capital theoretical lenses. This study will also proposed a new construct call ‘Passive Knowledge Sharing’ to help give better understand of SL effects on KS activities.