IT-Business strategic alignment has been one of the most important, persistent and interesting issues in both industry and academia. Not surprisingly, Service-Oriented Architecture (SOA) has attracted considerable attention among information technology (IT) practitioners due to its potential to address alignment of IT with business requirements. However, recent evidence indicates that many SOA initiatives have failed to enable this alignment in spite of rosy promises from vendors. This research examines the mechanism of IT-Business strategic alignment through dynamic capability-building processes to seek possible answers, and posits that IT infrastructure flexibility is a potential enabler of IT-Business strategic alignment under conditions of a dynamic external environment. First, the various facets of IT infrastructure flexibility within the context of SOA and IT-Business alignment are addressed. Then, the notion of environmental dynamism is introduced and the role of environmental dynamism in IT-Business alignment is identified. Finally, it is argued that IT infrastructure flexibility is a form of dynamic capability to help organizations achieve and maintain IT-Business alignment under higher degrees of environmental dynamism. We posit that the success of SOA in enabling alignment is contingent on environmental dynamism. Overall, this article contributes to both practice and research by shedding light on the largely ignored phenomenon, namely, of SOA failure and by exploring one fundamental factor affecting SOA initiatives’ success.