Fe42Mn28Co10Cr15Si5 high entropy alloy (DP-5Si-HEA) exhibited superplastic elongation of 550% at ε˙=10−3s−1 after complete tensile deformation at 700 °C. Pronounced Cr partitioning at testing temperature facilitated σ phase formation which assisted in stabilizing the grain size during deformation. Stable equiaxed fine-grained dual phase microstructure at all strain rates suggested dominance of grain boundary sliding over diffusion creep to maintain the superplasticity at the tested strain rate-temperature combinations. Cavitation along the gage region is evident, however, effective diffusional linkage of the cavities along the superplastic flow resulted in elongations >200% irrespective of strain rate at 700 °C. © 2019