Ctenosaura pectinata is a species of moderately large lizard in the family Iguanidae. The species is native to western Mexico.

The standardized English name is the western spiny-tailed iguana.^{: 58–59 p.} However, an earlier edition of standardized names applied the name Mexican spinytailed iguana to Ctenosaura pectinata.^{: 46 p.} Confoundedly the name Mexican spiny-tailed iguana was applied to Ctenosaura acanthura^{: 58–59 p.} which was referred to as the northeastern spinytailed iguana in the earlier edition of standardized names.^{: 45–46 p.} It has also been called simply the spiny-tailed iguana,^{: 506 p. : 216 p.} black spiny-tailed iguana,^{: 265 p.} Guerreran spiny-tailed Iguana, broad-ringed spiny-tailed iguana^{: 144 p.} among other common names.

The taxonomic status, relationships, and validity of a number of spiny-tailed iguana, particularly Ctenosaura acanthura, C. pectinata, and C. similis have an extensive history of confusion in both scientific and popular literature. The status and relationship of Ctenosaura acanthura and C. pectinata remains unstable (as of 2021) with some limited molecular evidence suggesting Ctenosaura acanthura is a synonym (the same species) of C. pectinata, while others recognize the two as allopathic, morphologically distinct species. The common names Mexican spiny-tailed iguana and black spiny-tailed iguana (among many other common names) have been loosely and informally applied to all three species at various times.

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