Supersonic nozzles have been applied in various jet‐induced fluidised bed attrition processes such as jet milling and Fluid Coking. In jet‐induced particle attrition, the penetration length into the bed of the jet issuing from the supersonic nozzle is a critical property that affects the attrition mechanisms. A numerical model was developed to predict the penetration length of jets issuing from a horizontal supersonic nozzle in high temperature fluidised beds, based on an Eulerian–Eulerian multiphase model and Granular kinetic theory. The predicted jet penetration lengths are in very good agreement with the experimental data and the predictions of Li's empirical correlation [Li, “Penetration of High Velocity Horizontal Gas Jets Into a Fluidized Bed at High Temperature”, in Fluidization XIII, S. D. Kim, Y. Kang, J. K. Lee, Y. C. Seo, Eds., Gyeong‐ju, Korea 2010; Engineering Conferences International, Gyeong‐ju, Korea 2010, pp. 893–900.]. The simulation results have also demonstrated that the fluidisation velocity and bed temperature have little influence on jet penetration length.