Particle–particle interactions, quantified by particle–particle restitution coefficient (e) and particle diameter () are two crucial parameters governing the flow hydrodynamics of dispersed gas–particle flows. In this work, a detailed numerical analysis has been carried out in order to get an insight into the effects of these two parameters on the jet penetration characteristics inside a bubbling gas–solid fluidized bed with a central jet. Specifically, the studies have been conducted to find out the effects of variations of these two parameters on the jet penetration length. It has been found that an increase in the value of particle diameter leads to a significant decrease in the jet penetration length for all other flow and physical properties remaining invariant. On the other hand, a gradual but substantial decrease in the jet penetration length has been observed with an increase in the values of e. Numerical investigations further reveal that there is no significant variation in the jet penetration characteristics for change in particle-wall interactions, quantified by the specularity coefficient ().