Empirical studies that reviewed e-government status in developing countries found that e-government research scholars preferred to ask, 'What is happening?' rather than 'Why is it happening?'. This showed little use of theory when it came to e-government study. Although high failure rates can happen anywhere, e-government research seemingly forgets to raise the question of why. To fill this gap, actor-network theory (ANT) was employed by this thesis as an analytical lens to investigate the failure case study of the Smart ID Card project, which was expected to revolutionise Thai public services with a single multi-propose ID card. Critical realism was the philosophical standpoint that framed the basic thinking in this study. It was intended to reflect on the e-government failure phenomenon; query its realities, and find a new set of answers. To achieve the aim of this study, both documentary research and in-depth interviews with relevant key persons were conducted, in order to synthesise the casual relationship and failure mechanisms in the Smart ID Card project.Firstly, the lens of ANT observed the causes of failure that originated from the problematization process, which referred to the role of the focal actor, the Cabinet, and less room for other actors (e.g. main public agencies and citizens) to negotiate in forming the actor-network of the Smart ID Card project. This led to unrealistic, unreachable objectives in the actor-network and opened the door to failure right from the beginning. Secondly, the interessement process, which had great importance in locking actors into position, was incomplete. Thus, the focal actor failed to enact standardisation, laws, regulations and a budget through negligence or lack of concern. This resulted in the failure of both human and non-human actors to enter the actor-network. Thirdly, the uncontrolled chaos in the enrolment process weakened endurance of the actor-network in facing its obstacles, for example, the emergence of a counter-network, which aimed to attack the main actor-network, the transformation of a non-human actor (Smart ID Card) that became a Trojan actor, and the instability of the focal actor. These obstacles brought disassociation among actors in the actor-network and led to the final moment, the betrayal. Fourthly, the betrayal resulted from errors in the earlier moments, which caused betrayal everywhere in the actor-network. All relevant human and non-human actors betrayed the actor-network by not working or supporting it properly in attempting to achieve its goals. Finally, the actor-network of the Smart ID Card project collapsed and could not function to reach its objectives. This meant that the Smart ID Card project did not revolutionise Thai public services as planned.This thesis is one of few theory based-works that contribute to the use of ANT modification as a unique vehicle for investigating failure phenomenon, especially in e-government projects in developing countries. The lessons learned from the story of failure in this study provide new solutions that open the door to successful e-government development.