<p>Mesoamerican ichthyofauna is recognized for its high taxonomic diversity. Representative groups include cichlids of the <i>Theraps-Paraneetroplus</i> clade, whose morphology is related to habitat use and the exploitation of food resources. Thus, changes in the lower pharyngeal jaw may represent a key feature in the evolution of feeding behavior in this group of fishes. We performed a geometric morphometric analysis to evaluate and compare the lower pharyngeal jaw shape among 20 species of Mesoamerican cichlids categorized in the herbivorous, scraper and sifter ecomorphological groups. Twelve landmarks and 32 semi-landmarks were used to describe the lower pharyngeal jaw shape. We also assessed whether the lower pharyngeal jaw shape exhibits phylogenetic independence. The most notable changes in the lower pharyngeal jaw were related to the shape of the posterior border in the dentigerous plate, length and width of the lateral processes. The detritivorous species <i>Oscura heterospila</i> and <i>Maskaheros argenteus</i>, as well as the sifter <i>Wajpamheros nourissati</i> were found to be the most highly differentiated in morphospace. However, most detritivorous and scraping species showed a notable overlap in morphospace, and some significant differences were detected between species and ecomorphological groups. The remarkable variation does not allow the recognition of clear patterns of differentiation, and no significant phylogenetic dependence was found in the lower pharyngeal jaw shape. However, some observed trends support the hypothesis of its relationship with the hardness of items consumed by the ecomorphological groups.</p>