The objective of this study is to investigate the thermal stability of dislocation structure and its effect on the creep behaviour for directed energy deposition-manufactured 316L stainless steel (DED-316L SS). Post-processing heat treatments with temperature ranging from 300-1200 °C were performed on the as-deposited DED samples. The microstructural changes induced by the heat treatment were correlated to the corresponding variations of the room temperature tensile properties and creep behaviour at 650 °C/225 MPa. Results show that dislocations produced during DED process tend to distribute uniformly, with only a few localized fine dislocation cells (average cell size of ~ 0.4 µm ) being detected. At 600 °C, the remaining dislocations rearrange and organize into a coarse dislocation cell structure with an average cell size of ~1.6 µm, leading to a slight decrease in yield strength but an increase in creep rupture time accompanying by a decrease of steady creep rate. At 800 °C, the annihilation of dislocations and destruction of dislocation cell structure, as well as elemental diffusion contribute to a significant drop in yield strength and creep rupture time with a noticeable increase in steady creep rate. Further increasing heat treatment temperature above 1000 °C removes the dislocation cell structure and elemental segregation on cell walls, which results in a continuous increase in steady creep rate. The present work demonstrates that by maintaining dislocation cells, post-processing heat treatment, i.e., annealing around 600 °C can effectively enhance the creep strength and lower the creep rate for DED-316L SS.