Reston virus (RESTV) is one of six known viruses within the genus Ebolavirus. Reston virus causes Ebola virus disease in non-human primates; out of all 6 ebolaviruses, it is one of the only two not known to cause disease in humans, but has caused asymptomatic infections. Reston virus was first described in 1990 as a new "strain" of Ebola virus (EBOV). It is the single member of the species Reston ebolavirus, which is included into the genus Ebolavirus, family Filoviridae, order Mononegavirales. Reston virus is named after Reston, Virginia, US, where the virus was first discovered.

RESTV was discovered in crab-eating macaques imported by Hazleton Laboratories (now Fortrea) in 1989. This attracted significant media attention due to Reston's location in the Washington metropolitan area and the lethality of a closely related Ebola virus. Despite its status as a level-4 organism, Reston virus is non-pathogenic to humans, though hazardous to monkeys; the perception of its lethality was compounded by the monkey's coinfection with Simian hemorrhagic fever virus (SHFV). Despite ongoing research, the determinants for lack of human pathogenicity are yet to be discovered.

Reston virus was first introduced as a new "strain" of Ebola virus in 1990. In 2000, it received the designation Reston Ebola virus and in 2002, the name was changed to Reston ebolavirus. Previous abbreviations for the virus were EBOV-R (for Ebola virus Reston) and most recently REBOV (for Reston Ebola virus or Reston ebolavirus). The virus received its current designation in 2010, when it was renamed Reston virus (RESTV).

A virus of the species Reston ebolavirus is a Reston virus (RESTV) if it has the properties of Reston ebolaviruses and if its genome diverges from that of the prototype Reston virus. For example, there exists Reston virus variant Pennsylvania (RESTV/Pen), differing by less than 10% at the nucleotide level.

While investigating an outbreak of Simian hemorrhagic fever (SHFV) in November 1989, an electron microscopist from USAMRIID named Thomas W. Geisbert discovered filoviruses similar in appearance to Ebola virus in tissue samples taken from a crab-eating macaque imported from the Philippines to a facility operated by Hazleton Laboratories (now Fortrea) in Reston, Virginia. The filovirus was further isolated by Dr. Peter Jahrling, and over the period of three months over a third of the monkeys died—at a rate of two or three a day.

Blood samples were taken from 178 animal handlers during the incident. Of them, six eventually seroconverted, testing positive using ELISA. They remained, however, asymptomatic. In January 1990, an animal handler at Hazleton cut himself while performing a necropsy on the liver of an infected Cynomolgus. Under the direction of the Centers for Disease Control and Prevention (CDC), the animal handler was placed under surveillance for the duration of the incubation period. When the animal handler failed to become ill, it was concluded that the virus had a low pathogenicity in humans.

Following the discovery of a filovirus in crab-eating macaques, an investigation tracing the infection was conducted by the CDC. The monkeys were imported from the Philippines, which had no previous record of SHFV or ebolavirus infections. It was suspected that the monkeys contracted both diseases while in transit aboard KLM Airlines before reaching Reston. Shipments were tracked to New York City, Texas, and Mexico City, none of which produced cases of infection.

By January 1990, Hazleton Laboratories recovered from its previous losses and began importing monkeys again from the same establishment in Manila that had provided the original animals. The imported monkeys became infected and were euthanized. In early February the CDC received reports of the disease in Alice, Texas. In March, the Division of Quarantine at the CDC secured a temporary ban on the importation of monkeys into the United States from anywhere in the world.