The importance of inter-organizational information systems (IOISs) to contemporary organizations has been demonstrated in research and practice. However, the effects of IOISs use on procurement practices in the public sector are less understood. The practice lens theory is drawn upon in this study to understand IOIS effects on procurement activities in the public sector of Ghana, a developing country context. The findings show the effects as: (1) successful online tendering processes; (2) unsuccessful online procurement execution processes; and (3) continuing use of paper-based document exchanges. The paper discusses how the effects resulted in a partial online procurement system and the failure to realize the desired benefits. It also discusses the constraints of a full-scale e-procurement platform deployment and use in developing country public sector and how they can be addressed.