Despite the phenomenal growth of Internet users in recent years, the penetration rate of Internet shopping is still very low and one of most often cited reasons is the lack of consumers’ trust [e.g. Hoffman et al., 1999]. Although trust is an important concept in Internet shopping, there is a paucity of theory-guided empirical research in this area. In this paper, a theoretical model is proposed for investigating the nature of trust in the specific context of Internet shopping. In this model, consumers’ trust in Internet shopping is affected by two groups of antecedent factors, namely, “trustworthiness of Internet vendors” and “external environment”. In addition, the effects of these factors on trust are moderated by the consumers’ propensity to trust. Trust, in turn, reduces consumers’ perceived risk in Internet shopping. As a step towards the rigorous testing of the model, a 30-item measurement instrument has been developed with its reliability and validity empirically tested. This research contributes to the development of trust theory in e-commerce and provides a validated instrument for the measurement of various important trust related constructs.