draws on the theory of belonging and the intrinsic motivation of altruism to explore the factors contributing to knowledge sharing behavior. Using a survey of 299 high school students applying for university after the release of the public examination results, we find that perceived online attachment motivation (b = 0.31, p < 0.001) and perceived online relationship commitment (b = 0.49, p < 0.001) have positive, direct, and significant effects on online knowledge sharing (R2 0.568). Moreover, when introduced into the model, altruism has a direct and significant effect on online knowledge sharing (b = 0.46, p < 0.001) and the total variance explained by the extended model increases to 64.9%. The implications of the findings are discussed