Camallanus tuckeri n. sp. is described from specimens found in the intestine of the side-necked turtles Emydura australis and Chelodina burrungandjii collected from several localities in the Kimberley region of Western Australia. The new species differs from Camallanus chelonius, a parasite of African turtles, in the shape of the buccal capsule ridges, the number of precloacal papillae in males (7 pairs in the new species vs. 6 pairs in C. chelonius) and spicule shape. Camallanus tuckeri n. sp. differs from Camallanus waelhreow in the shape of buccal capsule ridges and the inflation of vulva lips in females. The new species differs from Camallanus nithoggi by possessing a smaller number of incomplete buccal capsule ridges (up to 2 in C. tuckeri n. sp. vs. 4 or 5 in C. nithoggi), larger spicules, and the inflation of a posterior vulva lip that is lacking in C. nithoggi. Camallanus tuckeri n. sp. is the first nematode reported from Em. australis and the first endoparasite reported from Ch. burrungandjii.