Sleep deprivation (SD) appears common daily and has become a global public health problem. As a basic physiological need, sleep plays a vital role in the development and maintenance of individual physical and mental health, while SD may have various adverse effects on the body's normal physiological function. It is clear that SD can lead to cognitive impairment, such as slow response, decreased attention, impaired memory, and decreased executive function. Although sleep deprivation's negative effect on cognitive function has gradually become a hot topic, its related mechanism is unclear. This paper reviews the related studies of cognitive impairment caused by SD through the immune system, oxidative stress, synaptic plasticity, and gut‑brain axis and also analyzes the related studies of a variety of intestinal flora metabolites. Therefore, this provides a new perspective for exploring the mechanism of cognitive impairment caused by SD and provides some inspiration for the measures that can be taken to improve sleep disorders in the future.