Small businesses contribute significantly in economy. However, a significant number of small businesses fail in five to ten years. Can knowledge sharing in these businesses make a difference? Research has found that knowledge sharing enhances organisational competitiveness and growth in medium and large enterprises. However, there is a lack of empirical studies on knowledge sharing in the domain of small businesses. This research aims to close the gap by developing a model for understanding knowledge sharing in small businesses. The model will be primarily built on Lipshitz et al.'s naturalistic decision modelling approach, Rogers' innovation diffusion theory, and Ajzen & Fishbein's theory of reasoned action. The model presents various factors and variables affecting knowledge sharing in small businesses in detail, and thus has both theoretical and practical implications. For the model, hypotheses are proposed, which will be tested in future empirical studies.