Greek deities are a valuable touchstone for assessing the opposite or complementary notions of “unity and diversity”, and the same issue could have been be raised from the perspective of sacrificial ritual. In the context of ancient Greek religion, but also Greek culture as a whole, no generalizing statement can be made without testing it against the fragmented evidence from several hundred cities. Some scholars have therefore come to consider that we should speak of ‘Greek religions’ in the plural in order to reflect the fragmentation, considering both the representation of the gods and the rituals performed in their honour. Focusing on the divine world, this paper asks the question: which dimension prevails in the (ancient as well as modern) way of dealing with a Greek deity, the apparent unity given by its theonym or the diversity of its cult-places, images, cult-titles, etc.? The argument here is for addressing together unity and diversity, singleness and plurality when studying Greek gods.