Chaya (Cnidoscolus aconitifolius ssp. aconitifolius Breckon) is a domesticated leafy green vegetable of the Maya region of Guatemala, Belize, southeast Mexico and the Yucatán Peninsula, and parts of Honduras. Though relatively unknown outside of this area, evidence suggests that chaya was of significant importance to ancient peoples of the Yucatán Peninsula and perhaps elsewhere within the Maya region. Here we review what little research has been done on this impressive plant, as well as recount our own ethnobotanical investigation into its use as a food plant and medicine, and discuss its botany, nomenclature, and agricultural use. Due to its ease of cultivation, potential productivity, and above all its substantial nutritional value, we propose chaya as a potential crop for areas outside Mesoamerica.