Domestication and commercial production of the grasscutter, Thryonomys swinderianus, a large rodent, represents an important opportunity to secure sustainable animal protein for local communities in West Africa. To support production, DNA markers are required for population diversity assessment, pedigree analysis and marker-assisted selection. This study reports the application of double-digest RAD sequencing to simultaneously discover and genotype SNP markers in 24 wild and recently domesticated grasscutters. An initial panel of 1209 SNP loci was characterised from a total of more than 21 000 candidate loci containing single SNPs. This genome-wide resource represents the first application of its type to commercial production of a large rodent for food and advances the use of agricultural genomics in Ghana.