Pithias (died c. 422 BCE), also known as the Architect was a member of the Order of the Ancients, serving as Amorges' planner in the Order of Dominion branch in Messenia, Greece during the Peloponnesian War.
Within the order, Pithias served as Amorges' planner, operating in the seaport town of Aipeia. He was also acquainted with Artazostre, a fellow member of the Order and a member of the Daughters of Artemis. Prior to 422 BCE, he wrote a letter to Artazostre but was unable to locate her whereabouts. Therefore, he traveled to the Pedasos Camp to leave a message for her with her fellow Sisters of Artemis, though this trip left them with a poor impression of him.