Tantilla Onomastic is a comprehensive etymological and taxonomic reference for the genus Tantilla, produced as part of a larger series documenting the origins and meanings of snake scientific names. The work provides systematically annotated species- and subspecies-level epithets, including grammatical analysis, author–year attributions, linguistic derivations, and explanations of naming motivations drawn from historical literature. Where possible, interpretations are grounded in the original species descriptions to ensure accuracy and ICZN conformity. The document follows a standardized format intended for scholarly clarity and long-term usability. It serves as a resource for herpetologists, taxonomists, classical philologists, linguists, and historians of science seeking detailed insight into the linguistic roots, cultural context, and taxonomic history of the genus. This contribution forms part of an ongoing effort to build an accessible, curated archive of annotated snake etymologies. This contribution is part of a broader research program that may be consolidated into a comprehensive multi-volume reference on snake name etymology as the series progresses.