4660 Nereus, provisional designation 1982 DB, is a small (about 0.33 kilometres (0.21 mi)) asteroid. It was discovered by Eleanor F. Helin on 28 February 1982, approximately a month after it passed 4.1 million km (11 LD) from Earth.

Nereus is potentially an important asteroid with a high albedo. It is an Apollo and Mars-crosser, with an orbit that frequently comes close to Earth, and because of this it is exceptionally accessible to spacecraft. Indeed, because of its small size and close orbit, its delta-V for rendezvous of ~5 km/s is smaller than the Moon's, which is about 6.3 km/s.

Nereus makes seven approaches to Earth of less than 5 million km between 1900 and 2100. The closest will be on 14 February 2060, at 1.2 million km. The most recent closest approach was on 11 December 2021, when it was 3.9 million km away. During the 2021 approach, the asteroid peaked around apparent magnitude 12.6, requiring a telescope with around a 100mm objective lens to be visually seen. Its orbital period of 1.82 yr also puts it somewhat near a 2:1 orbital resonance with Earth, which means that an approximately 4-year mission could depart for and return from the asteroid on relatively near passes to the Earth.

Nereus is classified as a potentially hazardous asteroid (PHA), due to both its absolute magnitude (H ≤ 22) and its minimum orbit intersection distance (MOID ≤ 0.05 AU).

The asteroid is classified as E-type, so it could be potentially associated with aubrite meteorites (enstatite achondrites).