Decennatherium pachecoi Crusafont, 1952, is one of two giraffid species described from the Miocene of the Iberian Peninsula. This species is recovered exclusively from Vallesian faunas (MN9-10, late Miocene, 10–11 Ma). Despite being relatively well represented in the fossil record, except for the skull and ossicones, the complete vertebral column, and part of the upper dentition, its systematics and phylogenetic position among giraffids are the subject of debate. We update our knowledge of D. pachecoi, revising all Spanish material assigned to this species, as well as previously undescribed fossils. We reassess the systematics of Decennatherium, including its potential relationship with the second Iberian giraffid, the early Turolian Birgerbohlinia Crusafont, 1952, by means of the first cladistic analysis of the Giraffidae that includes Decennatherium together with the most relevant African and Eurasian taxa, both fossil and extant. Our results link Decennatherium with a ‘samothere’ clade, whereas Birgerbohlinia is nested within a ‘sivathere’ clade, thus refuting a previously assumed direct relationship between the two Spanish forms. Finally, we discuss some other possible finds of the genus Decennatherium in Greece, Turkey, and Iran.