In today’s hypercompetitive business environments hardly anyone questions the important role that information technology plays. The conventional wisdom is that IT is necessary for business survival and that careful deployment and management of IT resources and capabilities leads to enhance value for the business (Ying and Ram, 2004). Despite this recognition of information technology as a key enabler of organisational strategy (Preston and Karahanna, 2004), and despite recent investment in IT in Nigerian economy (Ajayi, 2003) an increasing number of organisations in this economy have found themselves unable to apply IT effectively (Modum, 1983). For corporate IT to be meaningful to knowledge workers it must recognise there exist key factors determining user acceptance of IT applications. A lack of such recognition often results in an underutilisation or simply failure of use IT by the knowledge workers (Ditsa, 2003; Oyesanya, 2005). To address key factors determining IT acceptance by knowledge staff in this economy we use social factors, habits and facilitating condition variables from Triandis’ model (1979) to extend the Technology Acceptance Model (Davis, 1993). The model hypothesises that behaviour positively relates to habits, facilitating conditions and social factors. Although this study is on going, it is a significant contribution to management practice and academic research. The proposed model redresses the limitations of the extant research model by accounting for intrinsic motivation and other social-cultural factors relevant to users’ IT acceptance and usage.