The central nervous system senses and responds to afferent signals arising from the body. These interoceptive afferents are essential to physiological homeostatic control and are known to influence an individual's momentary affect, cognition, motivation, and conscious experiences. Both sleep and interoception are tightly connected to physical and mental well-being. This review outlines the current knowledge about the interactions between interoception and sleep. It is demonstrated that there are complex, dynamic relations between sleep and sensory processes within each modality of interoception, including thermoception, nociception, visceral sensations, and subjective feelings about these sensations. A better understanding and appreciation of the intricate interrelations may facilitate management of functional somatic symptoms, chronic pain, insomnia, and other sleep and mental disorders.