Simulation is perhaps the most widely used approach to design and analyze manufacturing systems than to any other application area. Industry 4.0, the latest industrial revolution, also involves the use of simulation and other related technologies in manufacturing. In this study, our main ambition is to provide readers with a comprehensive review of publications which lie within the intersection of Industry 4.0, digitization in manufacturing, and simulation. To achieve this, we follow a two-stage review methodology. Firstly, we review several academic databases and discuss the impact and application domain of a number of selected papers. Secondly, we perform a direct Google Scholar search and present numerical results on global trends for the related technologies between years 2011 and 2018. Our reviews show that simulation is in the heart of most of the technologies Industry 4.0 utilises or provides. Simulation has significant role in Industry 4.0 in terms of supporting development and deployment of its technologies such as Cyber-Physical System (CPS), Augmented Reality (AR), Virtual Reality (VR), Smart Factory, Digital Twin, and Internet of Things (IoT). Additionally in terms of management of these technologies, simulation helps design, operate and optimise processes in factories.