Firsov is a lunar crater on the far side of the Moon. It is located to due south of the crater Lobachevskiy, and to the northwest of Abul Wáfa. The circular rim of this crater has a small outward bulge along the southern edge, and smaller bulges along the western side. The inner walls have slumped to form talus piles along the base. The low- albedo interior floor is nearly level and featureless.
Just east of Firsov, within unnamed, flat-floored crater is an unusual swirl pattern of high albedo, similar to the floor of Mare Marginis and to the Reiner Gamma feature.
Firsov is a Russian masculine surname, its feminine counterpart is Firsova. It may refer to
- Alissa Firsova (born 1986), Russian-British classical composer, pianist and conductor
- Anatoli Firsov (1941–2000), Russian ice hockey player
- Dmitri Firsov (born 1991), Russian football defender
- Elena Firsova (born 1950), Russian composer
- Ivan Firsov (c.1733–1785), Russian painter
- Oleg Firsov (1915–1998), Russian physicist
- Olga Firsova (born 1976), Russian basketball player
- Philip Firsov (born 1985), British painter and sculptor
- Vadim Firsov (born 1978), Russian football player