Single nucleotide polymorphisms (SNPs) are the most abundant form of genetic variation in eukaryote genomes and may be useful for selection of genetically distant parents for crossing in breeding programs. In this study, genome-wide SNPs of tall fescue (Festuca arundinacea Schreb.) were genotyped by using double-digest restriction-site-associated DNA sequencing to determine the genetic variation and differentiation among and within forage, turf and hybrid populations. After filtering, 16 036 SNPs were used to investigate genetic diversity and for structure analysis. SNP markers clearly differentiated the populations from each other. However, the hybrid population had a higher genetic similarity with the turf population than with the forage population. The results were confirmed by genetic differentiation (fixation index, Fst) and gene flow (Nm) statistics, so that low Fst and high Nm were observed between turf and hybrid groups, indicating less genetic distance and a high similarity between them. Based on the results of the weighted pair group method with arithmetic mean clustering, discriminant analysis of principal components and analysis of molecular variance, greater genetic differentiations were found among diverse turf, forage and hybrid populations, especially between turf and forage ones. In conclusion, numerous informative SNPs, natural allelic diversity-led domestication patterns, basic genetic variation statistics (e.g. Fst and heterozygosity) and population structures have multidimensional applicability for tall fescue genomics-assisted breeding.