Carcharodontosaurus (/ˌkɑːrkəroʊˌdɒntoʊˈsɔːrəs/; "shark-toothed lizard") is a genus of large theropod dinosaur that lived in Northwest Africa from about 100 to 94 million years ago during the Cenomanian stage of the Cretaceous. The taxon was first described in 1925 by French paleontologists Charles Depéret and Justin Savornin as Megalosaurus saharicus, based on two fossil teeth discovered in Algeria, which are now lost. A partial skeleton was discovered in Egypt as early as 1914 by crews of German paleontologist Ernst Stromer, although he did not report the find until 1931. Based on this specimen, together with the teeth previously described by Depéret and Savornin, Stromer established the genus Carcharodontosaurus and its type species (species a genus in named for) C. saharicus. Although the Egyptian skeleton was destroyed during World War II, it was subsequently redescribed as the holotype (name-bearing) specimen of a distinct carcharodontosaurid genus, Tameryraptor. In 1995, a large incomplete skull attributed to C. saharicus was discovered in the Kem Kem Beds of Morocco, which was officially proposed as the neotype (replacement holotype) in 2007. In the same year, fossils unearthed from the Echkar Formation of Niger were described and named as another species, C. iguidensis, though this taxon might belong to a different genus.

The type species reaching around 12 m (39 ft) in length and approximately 5–7 metric tons (5.5–7.7 short tons) in body mass, Carcharodontosaurus is one of the largest theropod dinosaurs known. It had a large, lightly built skull with a triangular rostrum (front of skull). Its jaws were lined with sharp, recurved, serrated teeth that bear striking resemblances to those of the great white shark (genus Carcharodon), the inspiration for the name. Though giant, its cranium was made lighter by greatly expanded fossae (depressions in bone) and fenestrae (holes in the skull), but this made the cranium more fragile than tyrannosaurids'. Studies of the bite force and tooth anatomy of Carcharodontosaurus have found it to have relatively low bite force compared to other large theropods. Despite the limited postcranial material known, is thought to have had small forelimbs, powerful hindlimbs, and a long tail that provided balance. Many gigantic theropods are known from North Africa during this period, including both species of Carcharodontosaurus as well as the spinosaurid Spinosaurus and the possible ceratosaur Deltadromeus. North Africa at the time was blanketed in mangrove forests and wetlands, creating a hotspot of fish, crocodyliforms, and pterosaur diversity.

In 1924, two teeth of Carcharodontosaurus were unearthed from wall cuts in different foggaras near Timimoun, French Algeria. These sediments came from the Cretaceous-aged Continental intercalaire Formation. The fossils were taken to the governor of Timimoun, Captain Burté, who gave them to French paleontologist Charles Depéret later that year. In 1925, Depéret and his colleague Justin Savornin described the teeth as coming from a new species of theropod dinosaur, Megalosaurus saharicus. These were the first fossils of theropods to be described from the region. The specific name saharicus refers to the Sahara Desert where the teeth had been found. Two years later, Depéret and Savornin reassigned the same teeth under the name M. (Dryptosaurus) saharicus, thereby placing the species in a subgenus. By accident, another species of Megalosaurus, M. africanus, was named by German paleontologist Friedrich von Huene based on the same teeth. It is therefore implied that it is a junior synonym of M. saharicus. The two original teeth described by Depéret and Savornin have since been reported as lost, being possibly kept in a collection in Algeria, Paris, or Lyon, and lack distinguishing characteristics from other carcharodontosaurids. Moreover, the genus Megalosaurus is known to have historically been a wastebasket taxon that included several species assigned without justification, the only currently recognised species being M. bucklandii. Later authors mentioned additional fossils from other provinces of Algeria that could belong to Carcharodontosaurus.

However, a partial skeleton later assigned to C. saharicus was first found in marls near Ain Gedid, Egypt, in early April 1914 by Austro-Hungarian paleontologist Richard Markgraf. Marls from this region derive from the Cenomanian-aged Bahariya Formation, one of many Cretaceous-aged sites of North Africa. In this formation, Markgraf did extensive collecting of dinosaur skeletons for his employer, German paleontologist Ernst Stromer of the Paläontologisches Museum München (Bavarian State Collection of Paleontology). Due to political tensions between the German Empire and then British-owned Egypt, this skeleton, since numbered as SNSB-BSPG 1922 X 46, took years to get to Germany. It was not until 1922 that they were transported overseas to Munich, where they were described by Stromer in 1931.

Stromer recognized that the skeleton's teeth matched the characteristic dentition of those described by Depéret and Savornin, which led to Stromer conserving the species name saharicus. However, he found it necessary to erect a new genus for this species, Carcharodontosaurus, for their similarities, in sharpness and serrations, to the teeth of the great white shark (Carcharodon carcharias). The genus name Carcharodontosaurus is therefore derived from Ancient Greek κάρχαρος (kárkharos), meaning "sharp, jagged", ὀδούς (odoús), meaning "tooth", and σαῦρος (saûros), meaning "lizard", and thus, "sharp-toothed lizard". In his 1931 and 1934 descriptions, Stromer designates the smaller of the two teeth originally described by Depéret and Savornin as the type specimen (name-bearing specimen) of the taxon. Thus, this tooth, although lost, must be considered as the lectotype (a later selected type specimen) of C. saharicus. World War II broke out in 1939, leading SNSB-BSPG 1922 X 46 and other material from Bahariya to be destroyed during a British bombing raid on Munich during the night of April 24/25, 1944. An endocast (cast of the interior of the braincase) was made and survived the war, being the only remaining relic of the specimen. However in 2025, this specimen was redescribed as the holotype of a distinct carcharodontosaurid genus, Tameryraptor. Following World War II, few major discoveries of Carcharodontosaurus were made. Dozens of isolated teeth and bones were referred to Carcharodontosaurus from sites across North Africa including in Morocco, Tunisia, Algeria, and Niger, but many of these fossils could belong to other theropods. Notably in 1960, French paleontologist Albert-Félix de Lapparent assigned teeth and bones from outcrops of the Continental intercalaire in North Africa to Carcharodontosaurus, however they were assigned to the genus without detailed taxonomic discussion or reasoning. Additionally, in 2025 Kellermann, Cuesta & Rauhut noted that many remains assigned to Carcharodontosaurus lack overlap and diagnostic features. Some of these fossils, such as several caudal (tail) vertebrae, may even belong to a sauropod.

Few discoveries of Carcharodontosaurus attributed material were made until 1995 when American paleontologist Paul Sereno found an incomplete skull during an expedition embarked on by the University of Chicago. This skull was found in the Cenomanian-aged rocks of the Lower Douira Formation, Kem Kem Beds, in Errachidia, southeastern Morocco. The presence of Carcharodontosaurus in this formation was first suggested in 1954 by French palaeontologist René Lavocat on the basis on fragmentary fossils. The skull, since catalogued as SGM-Din 1 at the Ministry of Energy, Mines and Environment in Rabat, Morocco, was first taken to the University of Chicago, where it was initially described in 1996 by Sereno and colleagues in Science. In 2007, SGM-Din 1 was officially proposed as the neotype (replacement type specimen) of C. saharicus due to the loss of the lectotype teeth and the similar age and geographic location to previously noted material. Several other fossils of C. saharicus have been unearthed from the Kem Kem Beds, such as dentary (lower jaw) fragments, two cervical (neck) vertebrae, and many teeth. Sereno and colleagues also assigned a multitude of cervical vertebrae described as the spinosaurids Sigilmassasaurus and "Spinosaurus B" to C. saharicus, reasoning that stout cervicals would be needed to carry the skulls of carcharodontosaurids. Later research proved otherwise, with the vertebrae being assigned to Spinosaurus aegyptiacus. In a 2016 study, it was suggested that the neotype of C. saharicus was similar to but distinct from the skeleton described by Stromer in the morphology of the maxillary (upper jaw bone) interdental plates. This conclusion was partially supported by the paper describing Tameryraptor, which noted several major differences between the Moroccan Carcharodontosaurus and the material described by Stromer. Because the neotype proposal was in accordance with the ICZN article 75.3 and 75.4, the describers of Tameryraptor agreed that SGM-Din 1 is a valid neotype.

In 2007, another species of Carcharodontosaurus, C. iguidensis, was described by American paleontologists Steve Brusatte and Paul Sereno. Fossils of C. iguidensis had been uncovered during an expedition to the Echkar Formation of Iguidi, Niger, with a partial maxilla (MNN IGU2) being designated the holotype. The species name iguidensis is after Iguidi, where the fossils were unearthed. Several other remains such as a braincase (part of skull surrounding brain), a lacrimal (skull bone in front of orbit), a dentary, a cervical vertebra, and a collection of teeth were assigned to C. iguidensis based on size and supposed similarities to other Carcharodontosaurus bones. However, a 2016 paper by Italian researchers Alfio Alessandro Chiarenza and Andrea Cau identified the non-holotypic material of C. iguidensis as belonging to Sigilmassasaurus (later assigned to Spinosaurus sp.) and a non-carcharodontosaurine, and therefore chose to limit C. iguidensis to the holotype pending future research. This conclusion has been supported by phylogenetic analyses (a study of the evolutionary relationships between taxa), with several finding the holotype and referred material of C. iguidensis as belonging to different taxa.

In 2013, another genus and species of carcharodontosaurid, Sauroniops pachytholus, was named by Andrea Cau and colleagues based on a single frontal (bone at front and top of skull), though more material may be referrable to the taxon. Sauroniops' validity has been questioned by several papers, with some stating that it is dubious (a species lacking diagnostic features) or a synonym of C. saharicus. This proposed synonymy has been disputed by others. Additionally, several remains belonging to an unnamed carcharodontosaurid distinct from Carcharodontosaurus, possibly the same as Sauroniops, were described by Paterna and Cau (2022). The South American genus Giganotosaurus was synonymized with Carcharodontosaurus in 1998 by Brazilian author Silvério Domingues Figueiredo and in 2010 by American paleontologist Gregory S. Paul, but no authors have since followed this assessment.