Ctenosaura acanthura, is a species of iguanid lizard found in eastern Mexico and extreme western Guatemala. The standardized English name is the Mexican spiny-tailed iguana. Confusingly however, an earlier edition of standardized names for Mexican herpetofauna called Ctenosaura acanthura the northeastern spinytailed iguana and applied the name Mexican spinytailed iguana to Ctenosaura pectinata, which was called the western spiny-tailed iguana in the second edition. It has also been referred to as the Veracruz spiny-tailed iguana and Gulf Coast spiny-tailed iguana. It is an egg laying species that is mostly herbivorous and a moderately large lizard commonly growing over one meter in total length.

Ctenosaura is a lizard genus commonly known as spinytail iguanas or ctenosaurs. The genus is part of the large lizard family Iguanidae and is native to Mexico and Central America. The name is derived from two Greek words: κτενός, meaning "comb", and σαύρα, meaning "lizard".