<p>High entropy alloys (HEAs) are widely preferred for structural applications due to their superior mechanical properties. Their industrial use will depend on the integration with other materials, where dissimilar joining will be fundamental. In this work, sound dissimilar joints between Al_0.3CoCrFeNi HEA and austenitic 316L stainless steel were obtained using gas tungsten arc welding. Microstructural characterization revealed the existence of a single-phase FCC structure in the fusion zone (FZ) of the joint, while the nucleation of the B2/BCC phase was noticed after imposing a post-weld heat treatment (PWHT). In the as-welded condition, hardness measurements confirmed the existence of a softening effect at the FZ compared to the original parent metals as a result of the coarse columnar dendritic growth. The dissimilar joint exhibited a decrease in tensile strength and ductility; however, this was significantly improved after the implementation of post-weld heat treatment. These outcomes suggest that these joints, especially after post-weld heat treatment, are suitable for structural applications.</p> Graphical Abstract <p>Gas tungsten arc welding of Al0.3CoCrFeNi high entropy alloy to AISI 316L austenitic stainless steel</p>