| Named By: | F. M. Dalla Vecchia in 1998 |
| Time Period: | Early Cretaceous |
| Location: | Croatia, Istarska Zupanija |
| Size: | Unavailable |
| Diet: | Herbivore |
| Fossil(s): | Partial remains |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Sauropoda | Diplodocoidea | Rebbachisauridae | |
Histriasaurus (HIS-tree-ah-SAWR-us) (meaning "Istria lizard") was a genus of dinosaur from the Early Cretaceous (Hauterivian to Barremian stages, around 130 million years ago). Its fossils, holotype WN V-6, were found near the town of Bale on the Istrian peninsula in Croatia, and described in 1998 by Dalla Vecchia. It was a diplodocoid sauropod, related to, but more primitive than, Rebbachisaurus. Phylogenetic analyses published in 2007 and 2011 placed Histriasaurus as the most basal member of Rebbachisauridae.
The type species, H. boscarollii, was described by Dalla Vecchia in 1998. The specific name honours the discoverer of the site, Dario Boscarolli. Although some authors consider Histriasaurus a dubious taxon, more recent papers support the original classification.