Abstract This paper evaluates the bearing capacity and failure mechanism of micropile groups in sand and clay. Micropiles are small-diameter piles (typically less than 300mm) that are generally used for structural support, underpinning, and in-situ earth reinforcement. The goal of this study was to compare the performance of micropile groups in sand and clay. Also, the bearing capacity and failure mechanism of the micropile group were evaluated and compared to a single equivalent concrete pile with a similar cap. For this purpose, bearing capacity diagrams were plotted using finite element-based Plaxis 3D Foundation software. Analysis results showed that the micropile group together with the soil within the group developed into a block and had higher bearing capacity in clay rather than loose sand. Also, the bearing capacity and failure mechanism of the micropile group in clay was similar to single equivalent concrete piles and the failure theories of piles in the literature.