A handheld fan, or simply hand fan, is a broad, flat surface that is waved back and forth to create an airflow. Generally, purpose-made handheld fans are folding fans, which are shaped like a sector of a circle and made of a thin material (such as paper or feathers) mounted on slats which revolve around a pivot so that it can be closed when not in use. Hand fans were used before mechanical fans were invented.

Fans work by utilizing the concepts of thermodynamics. On human skin, the airflow from hand fans increases the evaporation rate of sweat, lowering body temperature due to the latent heat of the evaporation of water. It also increases heat convection by displacing the warmer air produced by body heat that surrounds the skin, which has an additional cooling effect, provided that the ambient air temperature is lower than the skin temperature, which is typically about 33 °C (91 °F).

Next to the folding fan, the rigid hand screen fan was also a highly decorative and desired object among the higher social classes^{[citation needed]}. They serve a different purpose to the lighter, easier to carry hand fans. Hand screen fans were mostly used to shield a lady's face against the glare of the sun or fire.

Hand fans originated about 4000 years ago in Egypt. Egyptians viewed them as sacred objects, and the tomb of Tutankhamun contained two elaborate hand fans.

Archaeological ruins and ancient texts show that the hand fan was used in ancient Greece at least from the 4th century BC and was known as a rhipis, rhipister or rhipidion (Ancient Greek: ῥιπίς, ῥιπιστήρ or ῥιπίδιον). Fans were also used to keep flies away (like a fly-flapper), this kind of fan was less stiff and was named μυιoσόβη. Another use for a fan was to fan the flame, e.g. in cookery or at the altar.

Christian Europe's earliest known fan was the flabellum (ceremonial fan), which dates from the 6th century. It was used during services to drive insects away from the consecrated bread and wine. Its use died out in western Europe, but continues in the Eastern Orthodox and Ethiopian Churches.

There were many kinds of fans in ancient China. The Chinese character for "fan" (扇) is etymologically composed of the characters for "door" (戶) and "feather" (羽). Historically, fans have played an important aspect in the life of the Chinese people. The Chinese have used hand-held fans as a way to relieve themselves during hot days since the ancient times; the fans are also an embodiment of the wisdom of Chinese culture and art. They were also used for ceremonial and ritual purposes and as a sartorial accessory when wearing hanfu. They were also carriers of Chinese traditional arts and literature and were representative of its user's personal aesthetic sense and their social status. Specific concepts of status and gender were associated with types of fans in Chinese history, but generally folding fans were reserved for males while rigid fans were for females.

In ancient China, fans came in various shapes and forms (such as in a leaf, oval or a half-moon shape), and were made in different materials such as silk, bamboo, and feathers. So far, the earliest fans that have been found date to the Spring and Autumn and Warring States period. It was suggested by the Cultural Relics Archaeology Institute of Hubei Province that these fans were made of either bamboo or feathers and were oftentimes used as burial objects in the State of Chu. The oldest existing Chinese fans are a pair of woven bamboo, wood or paper side-mounted fans from the 2nd century BC. The Chinese form of the feather fan, known as yushan, was a row of feathers mounted in the end of a handle. The arts of fan making eventually progressed to the point that by the Jin dynasty, fans could come in different shapes and could be made in different materials. The selling of hexagonal-shaped fan was also recorded in the Book of Jin.