The okapi's closest living relative is the giraffe, with both species belonging to the family Giraffidae.
The giraffe and the okapi share several unique physical features, including long necks, prehensile tongues, and ossicones (horn-like structures). While the giraffe is much taller and has a longer neck than the okapi, the two species share similar cardiovascular and digestive adaptations for browsing on leaves in their respective habitats. The giraffe and okapi likely diverged from a common ancestor around 11-12 million years ago.