Agkistrognathus is an extinct genus of thalattosaurian which lived in the early to middle Triassic of British Columbia, Canada.

The genus name translates to "hook jaw" while the species name refers to Bob Campbell, who discovered the only known specimen.

[1] Agkistrognathus is a thalattosaurian, a group of marine reptiles with long, paddle-like tails and independently movable digits.

Agkistrognathus can be distinguished from other thalattosaurians due to having conical, closely spaced teeth which are smallest in the middle of the jaw and deep dentaries with hooked front ends.

[1] The holotype of Agkistrognathus campbelli, TMP 89.127.6, is a disarticulated skull including a maxilla, premaxilla, vomer, dentaries, angular, splenial, and other unidentified fragments.