The South African government has benefited to date from information technology in many ways. The importance of understanding and influencing South African citizens’ acceptance of E-Government services is critical, given the substantial investment in government communication, information system technology and the potential for cost saving. One of the most successful E-Government initiatives, the electronic filing system (eFiling), which allows tax returns to be filed electronically, has been available to taxpayers since 2006. Despite many taxpayers adopting this method, a large number are still using the traditional manual method of filing tax returns. Using behavioural intention to predict actual usage, this study utilised the decomposed theory of planned behaviour with factors adjusted specifically for South Africa as a developing country. This is done to identify the possible determinants of user acceptance of the eFiling system among South African taxpayers. Based on empirical data gathered from two questionnaire based surveys, perceived usefulness, perceived ease of use, compatibility, subjective norms, facilitating conditions, computer self-efficacy and trust proved to be significant determinants of behavioural intention. For taxpayers using the manual method, lack of facilitating conditions such as access to computer and internet resources was the most significant barrier to eFiling usage whilst taxpayers using the electronic method reported perceived usefulness as the primary determinant in their decision to use eFiling. Understanding these acceptance factors can extend our knowledge of taxpayers’ decision making and lead to better planning and implementation of future E-Government initiatives in South Africa and other developing countries. Die Suid-Afrikaanse regering het tot op datum gebaat van inligtingstegnologie in baie opsigte. Die belangrikheid van begrip en om burgers se aanvaarding van E-Regeringsdienste te beïnvloed is van kritieke belang, gegewe die belegging in tegnologie en die potensiaal vir kostebesparing. Een van die mees suksesvolle E-Regeringsinisiatiewe, die elektroniese liasseerstelsel (eFiling), wat toelaat dat belastingopgawes elektronies ingedien is, is sedert 2006 vir belastingbetalers beskikbaar. Ten spyte van baie belastingbetalers se aanneming van hierdie metode, gebruik 'n groot aantal nog steeds die tradisionele handmetode van die indiening van belastingopgawes. Met behulp van gedragsvoorneme om werklike gebruik te voorspel, benut hierdie studie die ontbinde teorie van beplande gedrag met faktore wat spesifiek aangepas is vir Suid-Afrika as 'n ontwikkelende land. Dit word gedoen om die moontlike determinante van die gebruikers van die eFiling-stelsel onder Suid-Afrikaanse belastingbetalers te identifiseer. Gebaseer op empiriese data wat uit twee vraelys gebaseerde opnames gekry is, beskou nut, gemak van gebruik, verenigbaarheid, subjektiewe norme, die fasilitering van voorwaardes, rekenaar self-doeltreffendheid en vertroue het beduidende determinante van gedragsvoorneme bewys. Vir belastingbetalers wat die handmetode gebruik, is 'n gebrek aan fasiliteringstoestande soos toegang tot die rekenaar en internet bronne die belangrikste struikelblok tot die gebruik van eFiling, terwyl belastingbetalers met behulp van die elektroniese metode berig beskou nut as die primêre bepaler in hul besluit om eFiling te gebruik. Begrip van hierdie faktore kan ons kennis van die belastingbetalers se besluitneming uitbrei en lei tot beter beplanning en implementering van toekomstige E-Regeringsinisiatiewe. / Dissertation (MCom)--University of Pretoria, 2014. / am2014 / Taxation / unrestricted