There is a general consensus that games are effective as learning tools. There is however, a lack of knowledgeregarding what makes online games effective as learning tools. The purpose of this study is therefore to answer the question:What are the factors influencing online game‑based learning effectiveness? The aim of this paper is to develop a conceptualframework that reflects the factors influencing online game‑based learning effectiveness. The conceptual frameworkcombines concepts from the Information Systems Success Model, Task‑Technology Fit Model and Flow theory. The studyused a quantitative method. Data was collected using an online instrument. The study used 134 respondents from mainlythe United Kingdom, United States and South Africa. The model was validated using confirmatory factor analysis and testedusing Smart‑PLS to assess path coefficients. The identified factors influencing Knowledge Improvement, the key measurechosen for learning effectiveness with online game‑based learning, are Game‑Task Fit, Flow (where Flow consists ofdimensions of Goal Orientation/Feedback and Concentration) and Perceived Usefulness. The utilitarian factors of Game‑TaskFit and Perceived Usefulness have a stronger effect on Knowledge Improvement than Flow. On the other hand Flow was theonly one of these three variables to have an influence on intensity and frequency of game use, suggesting a hedonicmotivation for intense and frequent game usage. These increases in game usage do not necessarily translate into KnowledgeImprovement suggesting that the link between game use and Knowledge Improvement may not be a simple linearrelationship. Game Quality influences Game‑Task Fit, while Information Quality influences both Flow and Game‑Task Fit.