No, lack of sleep does not directly cause fever. Fever is typically caused by an infection, illness, or inflammation in the body, and is usually accompanied by other symptoms such as chills, body aches, and fatigue. While lack of sleep can weaken your immune system and make you more susceptible to infections, it is not a direct cause of fever. If you are experiencing a fever, it is important to seek medical attention to determine the underlying cause and receive appropriate treatment.