1 Copyright © 2015, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 1 DOI: 10.4018/978-1-4666-8524-6.ch001 ABSTRACT Strategic planning of information systems is vital in the business environment and this is still an open issue in the management information systems research. Through planning, organisations develop ef- fective long-term use of information systems and subsequently ensuring the support of organisational objectives. This chapter develops a contingency model for measuring the success of strategic information systems planning in the context of medium enterprises. The contingency theory, as an analytical lens, advocates that organisational success can be achieved by matching organisational characteristics to the contextual factors. Drawing from this notion, this chapter postulates that the strategic information systems planning process, as a phase, may lead to successful planning. This relationship is moderated by contingency variables characterised by the presence of environmental uncertainty, organisational structure, government and policies, business strategy orientation and information systems maturity. This chapter studies the moderating role of contingency variables and identifes the infuential factors and their efect. 1. INTRODUCTION Information systems use in medium enterprises tends to primarily be for administrative and operational tasks. The most frequent applications in medium enterprises are transactional in nature. Beckinsale, Ram and Theodorakopoulos (2011) have recently stated that the failure to plan the introduction and exploitation of information systems and technologies in medium enterprises is due to the top management limita- tions. These include management having insufficient time to spend on future business developments and Towards A Contingency Model for Assessing Strategic Information Systems Planning Success in Medium Enterprises Ray M Kekwaletswe University of the Witwatersrand, South Africa