Anatomy of the oral cavity is a complex combination of numerous paired and unpaired muscles. A group of unpaired intrinsic muscles is right underneath the tongue mucosae, and they mostly control the more gentle movements of the tongue, like dorsum depression, for example. The second group of muscles is the extrinsic tongue muscles. Controlling more gross tongue movement, these three paired muscles (genioglossus, hyoglossus, and styloglossus) originate from bony structures and insert distally on the tongue body. Each muscle has a different orientation and shape that contributes to a characteristic anatomical aspect and function. The tongue can be divided into compartments and subunits. Each division has its own vascular blood supply and innervation. For this reason, tongue surgery can be considered a modular surgery. This chapter offers a comprehensive anatomical explanation of all of the different structures of the tongue. A strict knowledge of oral cavity anatomy is fundamental in order to plan and perform any surgical approach, especially in compartmental surgery.