Purpose This study aims to combine the theory of planned behave or (TPB) and the motivational framework to extend the research on online knowledge sharing (OKS) in an organization by exploring the factors that drive the knowledge sharing intentions (KSI) of posters and lurkers.

Design/methodology/approach A field survey with 501 employees in Vietnamese telecommunication companies is used to collect the data and a structural equation modeling approach with AMOS 25.0 is used to test all the hypotheses.

Findings Attitudes toward OKS and subjective norms influence online KSI for both posters and lurkers. Self-enjoyment has a stronger effect on the attitudes toward OKS for posters than lurkers. Self-efficacy, reciprocity and rewards only affect posters and not lurkers.

Research limitations/implications This study uses self-efficacy and self-enjoyment to represent intrinsic motivation and reciprocity and rewards for extrinsic motivation. Future research may use additional motivational factors to provide additional insights.

Practical implications Managers should pay greater attention to subjective norms and attitudes toward knowledge sharing to motivate all the employees to share knowledge with each other to improve organizational performance.

Originality/value This is the first study to combine TPB with the motivational framework to explore the factors that drive online knowledge sharing in an organization.