Premise of the study: Polymorphic markers were required for a native tree of the Mascarene Islands, Foetidia mauritiana (Lecythidaceae), to investigate the effects of fragmentation of lowland tropical habitats on tree mating systems and on gene flow. Methods and Results: Using microsatellite enrichment and next-generation sequencing, we identified 13 microsatellite loci (dinucleotide repeats). They were highly polymorphic in 121 trees sampled in the largest three populations on Réunion, revealing 2–17 different alleles per locus. Furthermore, they were found to be polymorphic in conspecific populations on Mauritius and in F. rodriguesiana from Rodrigues. Conclusions: These results indicate the utility of these markers to investigate genetic diversity, mating systems, and gene flow in a genus native to the biodiversity hotspot of Madagascar and the Indian Ocean islands.