Studies on fern gametophytes are lacking in comparison to their sporophyte counterparts, yet they are equally important to our understanding of fern ecology and evolution. Only one study has previously described the gametophytes of Microgramma. The goal of our study was to observe and document spore morphology and early developmental stages of the gametophytes of the fern, Microgramma brunei. Gametophyte development, morphological characters, and reproductive behavior were observed over the course of two months. A derivative of the classic “Farrar Type 1” cordiform gametophyte morphology was documented for M. brunei and a weak antheridiogen system was identified. This study is the first to focus on the gametophytes of a myrmecophytic species of Microgramma. These findings offer new insight into the biology of Microgramma brunei, a unique species of tropical fern.