The purpose of this paper was to investigate the antecedents for the utilisation of Web 2.0 tools to enhance Knowledge Management (KM) practices in academic libraries of Tanzania. Eight out of the twelve academic libraries were selected. Data gathered through questionnaires distributed to library staff (n= 278), with a response rate of 91.36%. The study used the DeLone and McLean Information System (IS) Success Model to come up with KMS Success Model. Thus, the KMS Success Model was empirically via a Structural Equation Modeling (SEM) approach to examine the antecedents for the utilisation of Web 2.0 tools for the KM practices in academic libraries. The findings reveal that service quality increases user satisfaction and intention to use Web 2.0 tools. Knowledge quality and system quality increase the intention to use and net benefits of using Web 2.0 tools. Further, user satisfaction increases intention to use and net benefits, whereas intention to use increases the net benefits of using Web 2.0 tools to enhance KM practices in academic libraries. This study was conducted to introduce new direction of KM practices through the application of Web 2.0 tools. DeLone and McLean IS Model was used to develop KMS success model which was tested and proved positive significant in KM practices and in facilitating libraries services.