This chapter gives an overview of some key themes in the early theories of sense perception. It covers early Greek theories (in particular those of the so-called Presocratics), Plato, Aristotle, and the early Peripatetics (Theophrastus and Strato). The comments on these first attempts at theorising senses come to us through the filter of Peripatetic reporting, which can be a challenge to their interpretation. In addition, it is argued that one can, to a degree, detect an increasing sophistication in the theoretical reasoning on the mechanism of sense perception. Finally, where possible, the chapter questions the standard hierarchy of the senses and highlights unusual cases of multisensory observations. The chapter provides the intellectual background for underpinning sensory studies of the ancient world, not just archaeology.