Representative grapevine accessions (Vitis vinifera) cultivated in Spain under the names Garnacha and Garnacha Tintorera, as well as their synonyms, were analyzed to determine genetic diversity and relationships. Both varieties are characterized by high levels of intravarietal morphological variation. Results confirmed the monophyletic origin of the Garnacha variety, which is represented by a main genotype with several phenotypic variants, likely corresponding to somatic mutations. In contrast, Garnacha Tintorera was characterized as a genetically heterogeneous group, which included three different teinturier genotypes. Possible parentage relationships among the teinturier varieties were identified and further confirmed using microsatellites, showing that all are derived from crosses performed in the nineteenth century to improve color intensity of well-known red wine varieties.