Shear failure in fibre-reinforced concrete (FRC) beams under fire conditions is challenging to predict due to its complex nature. As FRC is increasingly common to be used as building materials, there is an urgent need for a prediction tool for engineers to predict shear behaviour of FRC beams under fire. This work attempts to fill that demand by formulating a semi-analytical model based on the strut-and-tie model (STM) to predict the fire endurance of shear-critical FRC beams. The effect of continuity and the moment redistribution due to the stiffness loss of the heated span could also be considered. This novel model is shown to predict the failure time of six shear-critical fibre-reinforced lightweight aggregate concrete beams with good accuracy, highlighting its potential to be deployed as a straightforward and user-friendly prediction tool for engineers.