There have been many attempts to define Information Systems (IS) success but they have mostly been in the private sector. This paper reviews existing IS success models and then takes into account stakeholders as well as public sector perspectives in conducting qualitative case studies of 3 major Western Australian government agencies. Findings of the study identified key IS success variables relevant to the public sector and characteristics that distinguish the public from the private sector. By aligning success variables with these characteristics, it was possible to conceptualise an early theoretical IS success model for the sector.