This study presents the effect of modelling the microstructure of duplex stainless steels with different geometric shapes and sizes on the indentation test results. In this study, an indentation test is modelled on duplex stainless steel (DSS) sheets. The actual and simulated microstructures are modelled with finite element program. Actual microstructure is modelled on SEM image of microstructure. In simulated microstructures, the austenite phase is modelled with four different geometric shapes: circle, small square, big square and triangle. While the indentation depth is found to be 25.80 μm experimentally, an average depth of 22.58 μm is reached in the simulations. Also, the effect of microstructures of different phase ratios on indentation behaviour is investigated. When the austenite ratio increases by 13%, it is observed that the indentation depth increases by 2.1% on average. In summary, the actual and simulated microstructures in different shapes and sizes give similar deformation results.