Goddess I is the Taube's Schellhas-Zimmermann letter designation for one of the most important Maya deities: a youthful woman to whom considerable parts of the post-Classic codices are dedicated, and who equally figures in Classic Period scenes. Based on her representation in codical almanacs, she is considered to represent vital functions of the fertile woman, and to preside over eroticism, human procreation, and marriage. Her aged form is associated with weaving. Goddess I could, perhaps, be seen as a terrestrial counterpart to the Maya moon goddess. In important respects, she corresponds to Xochiquetzal among the Aztecs, a deity with no apparent connection to the moon.

The traditional Mayas generally assume the Moon to be female, and the Moon's perceived phases are accordingly conceived as the stages of a woman's life. The Maya moon goddess wields great influence in many areas. Being in the image of a woman, she is associated with sexuality and procreation, fertility and growth, not only of human beings, but also of the vegetation and the crops. Since growth can also cause all sorts of ailments, the moon goddess is also a goddess of disease. Everywhere in Mesoamerica, including the Mayan area, she is specifically associated with water, be it wells, rainfall, or the rainy season. In the codices, she has a terrestrial counterpart in goddess I.