The appearance of the blotched blue - tongued lizard is hinted in its scientific name: Tiliqua nigrolutea. Nigro and lutea mean black and yellow respectively. Indeed, this lizard is usually dark brown or black with yellow, cream or pink blotches on it. Although the blue-tongues are the largest members of the skink family (Scincidae), many of their characteristics differ from that of an average skink. First of all, they have an unusual body shape with a stout torso, short limbs and a thick, short tail. Furthermore, unlike smaller skinks, blue-tongues rarely lose their tails.

There are also differences between the males and females of the species. The males have proportionally bigger head and a more heavyset body. This is due to the shape of the two hemipenes (the male copulatory organs). Females are longer in length ((27-30cm to the males' 25-27cm). Because of this, the females are greater in mass weighing between 350 - 450g while males stay within the 300-350g range. (Cogger 2000, Jones and Edwards 1998).