Developing countries (DCs) have yet to fully benefit from the many advances in the Information Technology (IT) field, mainly due to problems such as lack of resources and systems infrastructure. COTS-Based Systems (CBS) entail purchasing a number of commercial off-the-shelf (COTS) software components, each satisfying some part of the requirements of the system and integrating these components into the required system. CBS offers a number of benefits that the DCs can access, such as reducing development and maintenance costs. Therefore, CBS can be used to provide support for DCs to improve their IT processes. The motivation for this thesis is an interest in improving the process associated with software systems development and procurements for organisations in DCs using CBS approaches. The research work focussed on investigating what processes (including traditional and soft factors) provide support for evaluating and selecting software components for CBS. This was achieved by three studies supported by a literature review. The first study was aimed at eliciting and synthesising current CBS practices from the UK and Zambia, which brought out problems associated with CBS and resulted in a focussed research direction. The second study identified and classified important processes (including traditional and soft factors) that support COTS software evaluation and selection for CBS from the UK, which facilitated the development of a social technical framework for COTS software evaluation (STACE). In the third study the framework was evaluated in Zambia. The findings of the third study indicate that, though the framework had some limitations, it was found useful, useable, satisfied user needs and valid for use. The main contribution of this research is STACE, a generic social-technical framework for COTS software evaluation and selection. It facilitates the examination of relationships between factors in different processes and their impact on COTS software evaluation and selection success, and therefore it can be used for further academic research. Furthermore, the framework can be used confidently to plan and implement COTS software evaluation and selection for CBS.