Antarctosuchus is an extinct genus of capitosauroid temnospondyl known from the Middle Triassic upper Fremouw Formation in the Transantarctic Mountains of Antarctica.

The generic name refers to Antarctica, where the only known specimen was collected, and suchus, a common suffix for temnospondyls Latinized from the Greek souchos, an Egyptian crocodile god.

The specific name, polyodon, is derived from the Greek πολύς (polús) "much", "many" and ὀδών (odon), "tooth", in reference to its unique teeth morphology.

To date, Antarctosuchus polyodon is the only other endemic temnospondyl species from the formation apart from Kryostega collinsoni, although indeterminate remains referred to benthosuchids and a cranial fragment assigned to Parotosuchus sp.

Other autapomorphic features of this taxon are a parachoanal tooth row that extends far posterior to the choana and occipital condyles which are set close to the midline.