Fourth-generation nuclear reactor concepts are focused on reaching a high level of fuel burnup, high coolant temperatures, and high safety levels (including passive safety systems). A design concept that fulfills these criteria is the high-temperature gas-cooled reactor (HTGR), which incorporates tristructural isotropic (TRISO) fuel particles for energy generation. Although development and qualification programs of TRISO fuel have shown positive results for their future utilization, uncertain issues related to the modeling of fuel performance still remain. In this paper, we review coated fuel particle performance analysis to demonstrate the current achievements and remaining obstacles in the field. The paper includes a qualitative assessment of different methods/models used for the modeling of important phenomena that occur in the coated fuel particle.