The relationship between urban sustainability of new smart cities and infrastructure projects has become integrated, and reflects the country's progress and prosperity, smart infrastructure projects classified in two main categories, the first is upgrading or retrofitting the built-up infrastructure and provide it with smart solutions, the second is establishing a new infrastructure for new urban sprawl or replace the built-up infrastructure with new one to cope with the global population increase. The concept of smart infrastructure is derived from the idea of the smart city which is described as a comprehensive system with different elements such as stakeholders, environment, economy, mobility, and living conditions of a given geographical space with efficient information communication technology (ICTs). Therefore, Stakeholders is one of the main success factors of Public-Private Partnerships (PPPs) in smart infrastructure projects, Hence, studying and analyzing stakeholders role in smart infrastructure projects through PPPs concept will decrease opposition leading to a non or ineffective implementation of the project as a result of the gap between the expectations of different stakeholders involved in PPPs on the desired process or outcome of the project. The presented study aims to establish a successful PPPs for smart infrastructure project phases with presenting a clear image of stakeholder's roles, and highlights PPPs challenges, characteristics, state's models, and agreements methods, especially with the high cost of these projects, to reach a set of recommendations aid to improve efficiency, quality, and affordable costs to achieve a sustainability whether in retrofitting or in the new urban sprawl.