Over the years, the world has moved towards an unprecedented level of urbanisation as half of the world’s total population live in cities. This trajectory of rapid urbanisation has greatly improved the modern economy as well as the standard of living. However, this fast-rising trend has also generated many new problems on the existing city infrastructures and amenities. This includes traffic congestion, waste management issues, scarcity of resources, human health concerns, deteriorating and ageing infrastructures. Thus, to prevent the rapid urbanisation from being a crisis, cities have sought to cater for the effervescent needs of city dwellers in an innovative way by making cities smart. Hence, a number of urban cities (e.g. Singapore, Dubai, New York, London, Barcelona, Madrid) have embarked on smart city projects to achieve prosperity, efficiency and competitiveness. These cities have embarked on critical projects such as the Three Gorges Dam, Sydney Opera House, Charles de Gaulle Airport (Terminal 2E) etc. These smart city concept projects consist of a set of coordinated activities with definite start and end dates to bring about a beneficial change or improvement to the problems posed by rapid urbanisation. However, judging these smart city projects have been controversial because it is widely held that project success means different things to different people and as such, it is mind-dependent. In order to substantiate this claim, the study explores the complexity associated with project success using relevant smart city real-life case studies. A significant observation from the explored case studies revealed that most of the projects did not perform excellently when examined using the iron triangle. It was observed that the positive or negative impacts (post-project benefit realisation) of each case study contributed towards the perception of success. Additionally, the success or failure of the case studies were subjectively defined by critical determinants that are external to the project. These factors were socially constructed around project stakeholders’ perception, either during the lifecycle or extended lifecycle of the project. Overall, project success remains a debatable issue because it transcends deterministic parameters but involves a combination of the achievement of project objectives and the satisfaction of project stakeholders.