The central problem of this dissertation arises from reflecting on Euthyphro’s often neglected final attempt to define piety and the discussion (elenchos) that follows. He claims that piety is knowledge of how to give to the gods what is pleasing in prayer and sacrifice. Socrates, without much argument, reduces Euthyphro’s answer to his earlier, already refuted one – that piety is what is dear to the gods – inviting the question of whether this is all the elenchos is meant to accomplish. If it is not, we should expect to find its purpose in the brief discussion that falls between Euthyphro’s definition and the final reduction of this definition to its predecessor. At the center of this discussion Socrates compares Euthyphronic piety to commerce. This comparison has classically been interpreted as showing Euthyphro’s definition to imply that humans can benefit gods, and since Euthyphro has elsewhere rejected this idea, his definition is refuted by contradiction. But this strands the reduction withoutpurpose, and scrutiny of the text suggests this is not the correct way to interpret the inference structure of this intervening discussion. In this dissertation I argue for two main theses: (i) the disambiguation thesis, which claims that the comparison to commerce is not the philosophical point of the elenchos, and does not result in the refutation of Euthyphro’s definition. It is instead intended to elicit which of two possible models of piety Euthyphro means to describe, the language of his definition being equivocal in at least one important respect, namely whether or not a met need necessarily confers a benefit upon the recipient; (ii) the translation thesis, which claims that there are some important observations to be made about the Greek of Euthyphro’s definition, observations that will make the dis- ambiguation thesis more plausible, and which are obscured by traditional translations of the passage under discussion. These observations concern kecharismena, a word often translated as ‘pleasing’, but is better understood as denoting a broad set of social and religious norms, and for which there is no simple English equivalent. Together, these two theses allow us to see that the main philosophical lesson of the last elenchos is that Euthyphro’s account of piety as ritual is an application of his more famous third attempt to define piety voluntaristically, and that any philosophical concerns over the last definition are consequences of it being an extension of the third one. This is why Plato puts the two side-by-side to close the dialogue, and we are kept from seeing this clearly when we take the comparison to commerce to be accomplishing the main work of the elenchos, rather than as clarifying Euthyphro’s answer so that its conceptual similarities to the previous answer are plainly visible. I conclude the project by defending the venerable view that Socratic piety is service to the gods instantiated by rational inquiry, and show how this model of piety is the antithesis to, and moral remedy for, Euthyphronic piety.