Tourism which is regarded as information intensive sector is the mostly affected sector by technology revolution and its traditional trading structures have been totally changed. The adoption and use of e-commerce in tourism sector is regarded as a tool to widen market reach and improve efficiency and effectiveness of business operations. The degree of impact of e-commerce use on business performance depends on the intensity of its usage in organization's key value-chain activities. However, the intensity of e-commerce use is influenced by technological, organizational and environmental (TOE) contextual factors. Based on TOE model and the existing literature on post-adoption use of e-commerce, a set of factors that affect the intensity of e-commerce use in Tanzanian tourism sector was identified. A survey was conducted with 181 Tanzanian tourism firms that have already adopted e-commerce and structural equation modeling (SEM) was used to analyze the data. The findings indicated that the scope of e-commerce use has a positive impact on business performance in terms of improved internal processes, competitive position, customer service delivery, overall business performance and increased customer base. The scope of e-commerce use is affected positively by pressure intensity and perceived benefits and negatively by barriers to e-commerce use. The findings have highlighted key areas that require immediate actions from both the government and private sector in order to promote a successful growth of e-commerce in the country.