Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Early Cretaceous (Toarcian to Berriasian). Fossil specimens have been found in England, France, Germany, Switzerland and Morocco.

 A recent phylogenetic analysis into the evolutionary relationships of Thalattosuchia did not support the monophyly of Steneosaurus, as the genera Machimosaurus and Teleosaurus both fell within Steneosaurus.

 Steneosaurus priscus is one of five thalattosuchian species known from the Mörnsheim Formation (Solnhofen limestone, early Tithonian) of Bavaria, Germany. Steneosaurus was the only teleosaurid known from this Formation, co-existing with four metriorhynchid species from the genera Dakosaurus and Geosaurus. It has been hypothesised that niche partitioning enabled several species of crocodyliforms to co-exist.

 From the semi-aquatic Oker locality in Lower Saxony, Germany (Kimmeridgian-age) two genera of teleosaurids (Steneosaurus and Machimosaurus) are known, in addition to the neosuchian genera Goniopholis and Theriosuchus. Steneosaurus and Machimosaurus are also found together in the same Tithonian-age deposits of western France.

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