For connections made with carbon-steel, the behaviour of the T-stub component is well understood and documented in the Eurocodes and is applied to T-stubs with two or four bolts per row. Researchers have investigated the application of the same Eurocodes guidance to T-stubs made with stainless-steel and having two and four bolts per row. However, there is very little information or studies on the post-fire behaviour of stainless-steel T-stubs and none found for those with four bolts per row. This study is aimed at providing a fundamental understanding of the post-fire behaviour of this connection component. Finite element analyses were carried out on 190 specimens with different parameters including temperature, T-stub flange thickness, width and strength, bolt diameter and grade, bolts spacing and edge distance. The results indicated four failure modes that are possible for the post-fire austenitic stainless-steel T-stub with four bolts per row. In all specimens, no circular yield patterns were recorded but only beam patterns occur at the web-flange intersection and at the bolt locations. A design approach for calculating the post-fire plastic resistance is proposed by introducing new and simplified formulas for determining the effective length of the plastic hinges for the various modes of failure. The accuracy of the design approach was validated using finite element modelling and experimental data from the literature.