The trigeminal nerve is divided into three branches—ophthalmic (V1), maxillary (V2), and mandibular (V3)—making it the largest of the 12 cranial nerves. Its main function is transmitting facial sensory information (pain, temperature, vibration, fine touch, crude touch, and proprioception) from the skin, sinuses, and mucous membranes. It also, via the mandibular nerve, transmits motor information to the muscles responsible for mastication as well as some smaller muscles of the soft palate and hyoid. This chapter will focus on the anatomy of the trigeminal nerve nuclei and its distal projections. Specific clinical lesions and disease states will be addressed in separate chapters. Regarding general references for the anatomy of the trigeminal nerve, please see sources (Woolfall, Coulthard, Br J Radiol 74:458–467, 2001; Netter et al., Netter’s clinical anatomy, Icon Learning Systems, Carlstadt, NJ, 2005; Bicanic et al., Acta Clin Croat 58:35–42, 2019; Standring et al., Gray’s anatomy: the anatomical basis of clinical practice, Churchill Livingstone/Elsevier, Edinburgh, 2016) for further reading which were used throughout the chapter.