We assessed the phylogeography of the Carib Grackle (Quiscalus lugubris), whose distribution includes eight subspecies in the Lesser Antilles and northern South America. We used the geographic distribution of variation in the mitochondrial genes ATPase 6 and ATPase 8 to assess the demographic history of the species and degree of concordance between phylogenetic relationships and subspecies assignments. We recovered a single haplotype in Guyana and French Guiana, which was shared by some samples from Trinidad, but Trinidad also hosts a second mitochondrial clade separated by 2.9% sequence divergence. Similarly, Venezuela is home to two sympatric clades separated by 3.6% divergence. Genetic relationships of island populations appeared largely discordant with currently described subspecies.