<p>Simulation of radiotherapy treatment setup is an integral part of the daily radiation oncology practice. Hence, simulation-based learning (SBL) plays a critical role in radiation oncology resident training. Such practical training approach enhances the precision of tumor delineation and the organs at risk (OARs), thus, directly influencing treatment efficacy and patient safety. Our review explores the application of the ADDIE (analysis, design, development, implementation, and evaluation) model in developing and implementing an SBL program of delineation skills training for the radiation oncologists. In this review, we discussed the phases of the ADDIE model as follows: analysis to determine the skills gap, design to tailor the training program to incorporate the advanced technology methods, development targets creating practical case scenarios and assessment tools, implementation assures the real-time feedback and the model-based debriefing sessions, and finally evaluation phase that employs the Kirkpatrick model. The application of the ADDIE model in SBL emphasizes that the training aligns with the educational needs. This enhances the clinical performance, and consequently, improves patient outcomes in radiation oncology. Applying the ADDIE model in SBL achieves the educational needs in radiation oncology delineation skills training, which will lead to enhance the clinical performance.</p>