Enterprise Resource Planning (ERP) systems are one of the technologies that many organisations, including Small and Medium Enterprises (SMEs), have adopted. However, most of commercial ERP packages are designed for large-scaled companies. More complex nature of business processes in large companies makes it difficult for SMEs to adopt commercial ERP packages. The high costs of ERP system implementation mean that SMEs need to seek for alternative solutions which are less expensive. One of these solutions is the Open Source ERP systems. The availability of Open Source ERP software and tools has not changed the uptake of ERP by SMEs. The above problems call for the development of a model which can be used by SMEs, to select Open Source ERP systems which will exactly match the business processes in SMEs. The general objective of this study was to develop a model that could guide the selection of Open Source ERP Systems by SMEs. Open Source ERP systems Selection Model was developed and used in evaluating common Open Source ERP Systems available in the market. The model consists of four components which include: (a) the evaluation criteria for selecting an Open Source ERP system, (b) factors related to the adopting organisation, (c) Open Source ERP system quality characteristics and (d) critical success factors for ERP systems implementation. The first objective which was to identify the components of Open Source ERP System Selection Model and these was achieved by the use of questionnaires. These components present the evaluation criteria which were used to evaluate the Open Source ERP Systems. The second specific objective was to evaluate existing Open Source ERP systems using the proposed model and provide their ranking. An evaluation was performed on ten Open Source ERP systems. Those Open Source ERP systems were then ranked according to the score they attained. From the evaluation, three best Open Source ERP systems were identified and introduced to few selected SMEs. The third objective of this study was to validate the Open Source ERP systems Selection Model. This objective was achieved through the survey in the SMEs where the three Open Source ERP systems were introduced. The balanced scorecard method was adopted for the measurement of the user satisfaction and ERP performance of the three systems. This study provides Open Source ERP systems Selection Model which guides the selection of the Open Source ERP systems. This study contributes to the current awareness and adoption of the Open Source ERP systems by SMEs, and this will lead to increase in the uptake of ERP by SMEs.