This is the first dictionary of the Zapotec language spoken in the pueblo of San Lucas Quiavina in the Tlacolula district of the Valley of Oaxaca, Mexico, and by immigrants to Los Angeles. Like all indigenous languages of the Americas, it is an endangered language. The language was never written down or studied before the beginning of research at UCLA in 1993. The Zapotecan language family is the largest indigenous language group in Oaxaca, and one of the largest in Mexico. The Dictionary's introduction includes a survey of the language's grammar, concentrating on phonology and morphology. It uses a new spelling system representing contrasts in vowel phonation and derived tone. Volume I contains over 9,000 entries and cross-references. Zapotec words and expressions are defined in both English and Spanish. Entries include examples of words used in natural sentences, as well as grammatical and cultural notes. Volume II contains English-Zapotec and Spanish-Zapotec indices containing over 20,000 brief entries, which refer the reader back to main entries in Volume I.