The richness of spider species on the foliage of Mexican ant-acacias in Los Tuxtlas (Veracruz), and Santiago Pinotepa Nacional (Oaxaca) was documented. A total of 11 species, grouped into five families were found;in Los Tuxtlas five species representing two families were identified, whereas in Santiago Pinotepa Nacional, the number of taxa was eight, belonging to five families. The richness of spiders in Santiago Pinotepa Nacional was higher than that found in Los Tuxtlas. In both locations <em>Nephila clavipes</em> Linnaeus and <em>Eustala illicita</em> O. Pickard-Cambridge, both from Araneidae, were found;these species had been previously reported as common inhabitants of Central American ant-acacias. The presence of <em>E. illicita</em> in Mexican myrmecophytic acacias was confirmed. A total of 10 species grouped into five families are reported for the first time inhabiting Mexican ant-acacias, increasing the richness of spider interactions documented in Mexico. This study showed that the occurrence of spiders in the <em>Vachellia-Pseudomyrmex</em> mutualism system has been overlooked and is likely more common than what has been reported until now. This opens an opportunity for the study of the evolution of spider-ant-plant interactions.