Mechanically alloyed high-entropy alloy (HEA) has taken considerable attention due to its ease of fabrication. Recent trend progresses towards the development of non-equiatomic HEAs to enhance the material properties compared to equiatomic alloys. Sintering behaviour of widely investigated equiatomic FeCoCrMnNi HEA has been reported. However, no report exists on the sintering kinetics of non-equiatomic HEA, when the concentration of a particular element is increased in the alloy powder. The present work attempts to study the isothermal and non-isothermal sintering behaviour of mechanically alloyed non-equiatomic Fe2CoCrMnNi HEA over a temperature range of 950–1100°C in an argon atmosphere. Activation energies for sintering and diffusivity parameters of Fe2CoCrMnNi HEA were calculated from dilatometric measurements through the sintering models. The result indicates the grain boundary diffusion as a dominating sintering mechanism for this alloy powder. © 2020 Institute of Materials, Minerals and Mining Published by Taylor & Francis on behalf of the Institute.