Illumina sequencing data was used to develop simple sequence repeat (SSR) markers for St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze], an economically important warm-season turfgrass. Polymorphism was observed in 190 of 215 designed SSR markers among a panel of eight diverse germplasm accessions. Of these, 94 were subsequently used to assess levels of diversity within a diverse collection of S. secundatum and pembagrass [Stenotaphrum dimidiatum (L.) Brongn.] germplasm. A total of 982 alleles ranging in size from 63 to 250 bp were amplified. Levels of polymorphism were high, with number of alleles amplified per loci ranging from 5 to 23 (μ = 10) and with polymorphic information content values ranging from 0.09 to 0.83 (μ = 0.54). Cluster and principal coordinate analyses of S. secundatum and S. dimidiatum accessions showed groupings based primarily on ploidy level. Analysis of population structure identified six subpopulations with some admixture present among them. Additionally, the ability of these newly developed SSR markers to uniquely identify specific cultivars was assessed. A set of five SSR markers were capable of producing unique banding patterns for all but two cultivars. These markers, the first developed for the species, should be useful for linkage mapping, diversity and pedigree analyses, accurate varietal identification, and marker-assisted selection in St. Augustinegrass. © Crop Science Society of America.