Journal of Information & Systems Management Anusorn Panya, Lachana Ramingwong 4 3 2014 Trust is essential for the development of E-Commerce web sites. Owners or developers of such web sites need to know the important characteristics of trust and how to display them on their web sites. In order to do so, the factors that influence user trust must be studied. Therefore, there is a clear need of a framework for building trust in E-Commerce web sites, especially Business-to-Consumer E-Commerce in Thailand where trust is the main challenge. This paper proposes a trust building framework for B2C E-Commerce web sites based on the questionnaire modified from E-S-QUAL and E-RecSQUAL. The analysis of service quality and factors results in understanding and insights of customer perception and expectation toward the web site. The important factors are also identified. (Abstract)