The Modular Building System (MBS) is increasingly popular and promoted due to the inherent advantages over conventional construction. Fire performance of a building has become a crucial design consideration because of the recent detrimental fire accidents. However, for modular buildings, there has been less previous evidence of research on the fire performance. Investigations become necessary since double skin wall and floor modular panel systems are involved in MBS in contrast to conventional buildings. Therefore, this work investigates the fire performance of Light-gauge Steel Framed (LSF) modular wall panels with different configurations through numerical analyses. Heat transfer numerical models were developed and validated against the full-scale fire test results comparing the time-temperature response. The validated numerical models were subsequently extended to analyse the fire performance of conventional and modular LSF wall panels. This includes 16 modular wall configurations with single and double fire resistance plasterboard linings and three different insulations, namely rock wool, glass fibre and mineral wool. The structural fire resistance time was determined using the established Load Ratio (LR) vs critical Hot-Flange (HF) temperature correlation. The results demonstrated that there is no noticeable difference in the structural fire resistance time between the modular and the corresponding mapped conventional LSF wall configurations. However, modular wall panels experience enhanced insulation fire resistance up to 170% for single-lined plasterboards and up to 80 % for double-lined plasterboard configurations. The analysis also yields that there is no significant influence of the choice of insulation material between rock-wool, glass-fibre and mineral-wool on structural fire resistance.