The study on which this article reports examined the determinants of usage of an online learning management system (LMS) by fourth level business students at a South African open and distance learning university using an extension of the widely used technology acceptance model (TAM) as a theoretical basis. A survey was conducted among students at their annual summer school, with 213 usable questionnaires being returned. The findings suggest that perceived usefulness and perceived ease of use as core aspects of the TAM and TAM2 models are confirmed, and study relevance (job relevance in the TAM2 model) and facilitating conditions as extensions are confirmed also. However, other elements of the TAM2 model and extensions were not confirmed by the research, while the relationships between these constructs, behavioural intention and LMS use were significant but not particularly strong. Thus, despite the ostensible robustness of the underlying structure and dimensionality of the TAM core constructs, its usefulness as a model to explain usage in this context and in a setting where acceptance and usage patterns have been established over prolonged periods of time is limited. The findings do, however, suggest certain initiatives to assist in increasing the perceived usefulness of the LMS. (Contains 2 figures and 6 tables.)