This dissertation examines the relationship between language and reality in Parmenides, Heraclitus, and Aeschylus. I examine the idea that certain aspects of reality best apprehended through language, rather than the senses. In investigating the relationship between language and reality, this dissertation seeks to shed light on an early stage of an idea of considerable importance in Greek thought, one which links two significant intellectual themes: the division between appearance and reality, and the ambiguous power of language to inform or mislead. In the first chapter, I argue that Parmenides links our use of language with our knowledge of reality, and insists that language must be reconciled with reality in order for us to attain knowledge. Parmenides claims that we mortals fail to understand the true existence of the non-perceptible, and so we commit errors in thought and speech that vitiate our understanding of the perceptible world too. In chapter two, I argue that Heraclitus creates an entirely new use of language to reflect the oneness of reality and the identity of opposites. When Heraclitus says that day and night are the same, he means not only that the physical phenomena day and night are equivalent, but more importantly that the concepts day and night are a unified whole. Likewise, the words “night” and “day” each signify this single unified concept, so that there is paradoxical unity within each individual word. In chapter three, I argue that for Aeschylus, the relationship between language and reality is not only an epistemological problem, but also a social problem. The “reality” in question in Aeschylus’ Oresteia is the socio-ethical reality of the world in which the characters live. Aeschylus provides a resolution for the problem of language and reality in the jury trial at the end of the Eumenides. My analysis shows that for each thinker, correct language is vital for acquiring and communicating knowledge, particularly knowledge of non-perceptible reality, such as concepts and conceptual structures. I conclude that the commonality among these thinkers is due to an emerging acknowledgement of the importance of non-perceptible aspects of reality.