Abstract— Simulation models are widely used to reflect the behavior of a certain system and to study the effect of specific changes on the overall system. Simulation models are used in the construction industry for problem solving, optimization or testing new methods. Implementing a new simulation model may face some challenges unless verification and validation of a model are performed to show that the model has achieved its objectives. Some simulation studies do not apply a systematic validation process to validate their model because of many reasons such as time, cost and the availability of data. This research project focuses on studying the validation methods used in construction simulation studies and how they are frequently used. Sixty papers were collected from three different sources: Automation in construction, Journal of Construction Engineering and Management, and Winter Simulation Conference. The selected 60 papers were studied, and it was found that not all simulation studies apply systematic validation processes. It was also found that the comparison with real data is the most widely used validation method in simulation studies. Besides, on the other hand, the comparison with expert opinion shows a good practice since it involves experts from the construction industry in the model building stage or by using their experience to evaluate the model output in terms of reliability.