美国毒蜥（学名：Heloderma suspectum）亦称为希拉毒蜥或是钝尾毒蜥，英文有「Gila Monster」之称，因为希拉河盆地（Gila River Basin）而得名。美国毒蜥是世界上仅有的两种毒蜥的其中一种〈另一种是墨西哥毒蜥〉，主要就分布在美国西部,南部各州,以莫哈维沙漠(Mojave)为中心,延伸进入墨西哥， 美国毒蜥有两个亚种:分布区北部的黑带美国毒蜥(H. s. cinctum)和分布区南部的网纹美国毒蜥(H. s. suspectum)，体色表现为通体金黄或橘色，上面布满黑色斑纹。

The Gila monster (Heloderma suspectum, /ˈhiːlə/ HEE-lə) is a species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora. A heavy, slow-moving lizard, up to 60 cm (2.0 ft) long, the Gila monster is the only venomous lizard native to the United States and one of only two known species of venomous lizards in North America, the other being its close relative, the Mexican beaded lizard (H. horridum). Though the Gila monster is venomous, its sluggish nature means it represents little threat to humans. However, it has earned a fearsome reputation and is sometimes killed despite being protected by state law in Arizona.