Stephanorhinus is an extinct genus of two-horned rhinoceros native to Eurasia and North Africa that lived from the Late Pliocene until their extinction in the Late Pleistocene. Species of Stephanorhinus were the predominant and often only species of rhinoceros in much of temperate Eurasia, especially Europe, for most of the Pleistocene. The last two species of Stephanorhinus – Merck's rhinoceros (S. kirchbergensis) and the narrow-nosed rhinoceros (S. hemitoechus) – went extinct during the latter half of the last glacial period.

The taxonomic history of Stephanorhinus is long and convoluted, as many species are known by numerous synonyms and different genera – typically placed in Rhinoceros and Dicerorhinus – for the 19th and most of the early 20th century. The genus was named by Miklós Kretzoi in 1942. The first part of the name, Stephano-, honours Stephen I, the first king of Hungary (the describer, Kretzoi, was Hungarian). The second part is from rhinos (Greek for "nose"), a typical suffix of rhinoceros genus names. Genomes obtained from Stephanorhinus kirchbergensis suggests that Stephanorhinus is more closely related to Dicerorhinus (which contains the living Sumatran rhinoceros) and Coelodonta (which contains the woolly rhinoceros), than it is to other living rhinoceroses, and is more closely related to Coelodonta than to Dicerorhinus, with the date of divergence between Coelodonta and Stephanorhinus estimated at around 5.5 million years ago, with the estimated split between their last common ancestor and Dicerorhinus estimated at around 9.4 million years ago. The genus is also closely related to the fossil rhinoceros genera Dihoplus and Pliorhinus, known from the Late Miocene and Pliocene of Eurasia, which may be ancestral to Stephanorhinus. Although a 2019 study based on dental proteomes suggested that the genus was paraphyletic with respect to Coelodonta, later studies have consistently recovered Stephanorhinus as monophyletic.

Truncated cladogram of Rhinocerotinae, showing the position of Stephanorhinus relative to living and Pleistocene rhinocerotine species based on morphological and genetic data, after Borrani et al. 2025.

Species of Stephanorhinus were large-sized rhinoceroses, with body masses estimated between 1,500–3,000 kilograms (3,300–6,600 lb). Stephanorhinus species have proportionally long (dolichocephalic) skulls. They had two horns, a frontal and a nasal horn. The nasal septum was partially ossified (turned to bone), which connected the nasal bones with the premaxillary bones. The incisors were either lost completely or very heavily reduced in size. Species of Stephanorhinus differ from each other in skull shape and angle of the skull held relative to the ground, in the morphology of the teeth, and in the length and shape of the limb bones.

The oldest unambiguous known species of the genus are from the Pliocene of Europe. The former species "S." pikermiensis is currently considered to belong to Dihoplus. "S." megarhinus (known from the Late Miocene-Pliocene of Europe, Anatolia, and Transbaikalia, spanning from around 6.7-3.5 million years ago. ) and "S." miguelcrusafonti from the Early Pliocene of Western Europe were assigned to the new genus Pliorhinus in 2021, but their placement as a separate genus has been disputed, with other authors supporting their placement in Stephanorhinus.

The position of Stephanorhinus? africanus from the Middle Pliocene of Tunisia and Chad is uncertain.

Stephanorhinus jeanvireti, also known as S. elatus is known from the Late Pliocene and Early Pleistocene of Europe. Its remains are relatively rare in comparison to other Stephanorhinus species. Specimens are known from the Late Pliocene of Germany, France, Italy, Slovakia and Greece, and the Early Pleistocene of Romania, with its temporal span being around 3.4 to 2 million years ago (Ma).

Stephanorhinus etruscus first appears in the latest Pliocene in the Iberian Peninsula, around 3.3 Ma at Las Higueruelas in Spain and before 3 Ma at Piedrabuena, and during the latest Pliocene at Villafranca d'Asti and Castelnuovo di Berardenga in Italy and is abundant during most of the Villafranchian period in Europe, and is the sole rhinoceros species in Europe between 2.5 and around 1.3 Ma. A specimen is known from the Early Pleistocene (1.6-1.2 Ma) Ubeidiya locality in Israel. During the late Early Pleistocene, it is largely replaced by S. hundsheimensis. The last known records of the species are from the latest Early Pleistocene of the Iberian peninsula, around 0.9-0.8 Ma.