Saurophaganax ("lord of lizard-eaters") is a dubious, chimeric genus of large saurischian dinosaur, possibly a sauropod, from the Late Jurassic (Kimmeridgian) Morrison Formation of Oklahoma, United States.

In 1931 and 1932, John Willis Stovall uncovered remains of a large theropod near Kenton in Cimarron County, Oklahoma in layers of the late Kimmeridgian.

[4] In 2024, Danison and colleagues revised the referral of various specimens assigned to Saurophaganax maximus including the fragmentary holotype neural arch (OMNH 1123) based on their comparative analysis.

[10] In 2019, Rauhut and colleagues noted that the definitive taxonomic placement of Saurophaganax within Allosauroidea is unstable, being recovered as a sister taxon of Metriacanthosauridae or Allosauria, or even as a basalmost carcharodontosaurian.

The Morrison Basin where dinosaurs lived, stretched from New Mexico to Alberta and Saskatchewan, and was formed when the precursors to the Front Range of the Rocky Mountains started pushing up to the west.

[15] The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs such as Barosaurus, Apatosaurus, Brontosaurus, Camarasaurus, Diplodocus, and Brachiosaurus.

[17] Other vertebrates that shared this paleoenvironment included ray-finned fishes, frogs such as Eobatrachus, salamanders, turtles, sphenodonts, lizards, terrestrial and aquatic crocodylomorphs like Goniopholis, and several species of pterosaur like Kepodactylus.