Loop heat pipes (LHPs) are efficient and reliable heat transfer systems whose operation is based on the liquid–vapour phase-change phenomenon. They use the capillary pressure generated in a porous structure to passively circulate the fluid from a heat source to a heat sink. In this paper, an exhaustive literature review is carried out in order to investigate the existing steady-state models of LHPs. These models can be divided into three categories: numerical models of the entire system, numerical models of the evaporator and analytical models. The parameters and physical mechanisms taken into account in the different approaches are described and compared. Finally, a synthesis summarizes all the steady-state models from the literature in a comprehensive table where all the parameters having an influence on the system performance are listed. The review shows the evolution of the modelling works in the past 15 years and highlights the increasing development of 3D investigations.