The brood-parasitic mite has devastated colonies of the honey bee Apis mellifera. Colonies of A. mellifera, untreated with acaricides, typically die within three years of Varroa infestation. However, this removes the selective pressure for the evolution of Varroa-resistance traits in the bees. Although initial colony losses can be high, when populations are left untreated with acaricides, selection can drive the evolution of resistance traits. Within these resistant populations, the inhibition of Varroa reproductions is a common trait. My PhD aimed to investigate the genomic basis for the evolution of Varroa resistance in two populations of A. mellifera: one from Gotland, Sweden, and the other from near Toulouse, France. I identify genes and physiological pathways linked to resistance in these populations and consider what they can tell us about the reproduction of Varroa as well as the implications of these results for the breeding of Varroa-resistant honey bees.