—Acoustic communication has been reported in the order Squamata, although there are still few studies on this behavior, which constrain our understanding of the functionality and evolution of vocalizations produced in Squamates, especially in the clade Unidentata. The Balsas Basin Whiptail (Aspidoscelis costatus costatus) is an endemic lizard to the western Mexican area, which has been anecdotally reported to vocalize. We took the first step in understanding the functionality of the sound production of this species by determining when individuals vocalize, characterizing these sounds by measuring the spectro-temporal variables, and assessing the effect of the temperature on vocal production. We collected 19 female and six male A. c. costatus and obtained 24 vocalizations from seven females and four males. Vocalizations were tonal, short, and relatively low-pitched with several harmonics. Individuals vocalized when caught or cornered, which we define as distress calls. At high body temperatures, lizards vocalized more than those at lower body temperatures. Finally, we compared the vocalizations produced by A. c. costatus with those reported for other lizard species, especially with the anecdotal reports within the genus Aspidoscelis.