General anesthesia is a procedure performed every day worldwide due to numerous surgical and nonsurgical indications. It produces pronounced changes in the patient’s body homeostasis, primarily due to the drugs used to achieve the state of general anesthesia. The most frequent components of general anesthesia are various sedative, analgesic and hypnotic drugs, all of which exert their effects through acting on receptors in the central nervous system. The effects produced by these drugs are essential to the basic characteristics of the state of general anesthesia. However, it is evident that some of the effects of general anesthesia surpass the time actually spent in the state of general anesthesia. The effects of general anesthesia on the quality of sleep is of particular interest in this matter and has received increasing attention over the past few decades, thus becoming the topic of numerous researches. As general anesthesia is most commonly utilized to enable performing various surgical procedures, one of the greatest challenges in testing how general anesthesia affects the quality of sleep is in separating the effects on sleep produced solely by general anesthesia from the effects produced by surgical procedures and in hospital stay (tissue trauma, pain, intensive care unit environment, etc.). It is why animal studies have proven useful in providing conditions difficult to replicate in human studies due to both practical and ethical reasons and therefore comprise a significant fraction of studies related to this topic. Although fewer in numbers, human studies have been performed and are of great value in better understanding the answers to questions related to general anesthesia’s influence on sleep. Both animal and human studies, although diverse in the particular focus of each study, confirm that general anesthesia not only produces a state comparable to sleep in more than just appearance, but may even satisfy the need for certain stages of homeostatic sleep. The studies also agree that general anesthesia greatly influences the quality of sleep in the postanesthetic period. The magnitude and length of this influence are dependent on many factors, including the choice of drugs utilized to achieve the state of general anesthesia and the time of day at which the procedure is set and may last for days and even months. As sleep is a vital component of quality of life and is essential for achievement of optimal function of various organ systems, it is not surprising that it is also a key element of postoperative recovery. Further research in this area is required to better understand this topic and to add to better understanding of general anesthesia, as well as improving patients’ quality of life in a long-term manner.