Settlement on the site of the modern city known since the middle of the 17th century, In 1701, mentions the settlement Unsteady, founded by old believers who fled the persecution of the official Church. The name from the old swell "precarious place, Slough", - according to historians, a settlement was founded at the place flooded in the floods; after her transfer to the new location the name has remained.
County town Novozybkov, Chernigov province from 1809
In 1856 in the town of Novozybkov, Chernigov province had 3 churches, 1004 homes, 142 shops.
In the 19th and early 20th centuries Novozybkov - the largest center of the manufacture of matches. The first factory was built in 1864, and later in the city and County operated 8 match factories.
In 1887, passed through the city of Bryansk-Gomel railway, in 1899, railroad Novozybkov - Novgorod-Seversky.
In 1895 there were 119 1692 stone and wooden buildings, 165 retail stores, 9 hotels, 30 plants. 4 times a year trade fairs were organized.
During the great Patriotic war of 1941-45 Novozybkov was occupied by Nazi troops from August 16, 1941 In the forests of the Novozybkov began forming partisan unit AF Fedorov. The town was liberated on 25 September 1943, troops of the Bryansk and Central fronts in the Bryansk and Chernigov-Pripyat operation.
Since 1944 in the composition of the Bryansk region.
In the accident of Chernobyl 1986 Novozybkov district has been in a zone of radioactive contamination. Area not suitable for human habitation starts 1 km from the city.