Nieuwleusen (Low Saxon: Ni'jlusen) is a town in the Dutch province of Overijssel with 9300 inhabitants as of 2021. In the 2001 municipal reform, most of the former municipality of Nieuwleusen was incorporated into the municipality of Dalfsen. Some parts of the former municipality, including the Lichtmis area, was added to the neighbouring municipality of Zwolle.

The provincial road N377 (the 'Den Hulst') runs along the town, going from Hasselt in the west to Coevorden in the east. To the north are the hamlet of Punthorst and the Staatsbos state woodland in the municipality of Staphorst. South of Nieuwleusen is Dalfsen, a slightly bigger town from which the municipality takes its name. To the west, provincial road N377 and highway A28 meet at De Lichtmis, the location of a former military bulwark which provided access to the north of the country. Nieuwleusen is situated between the Vecht and Reest rivers to the south and north respectively, and is counted as part of the historical region of Salland, or latterly the (Overijssels) Vechtdal (Vecht Valley - a usage in tourism).

The town has a northern and an older southern half (today called Nieuwleusen-Noord and Nieuwleusen-Zuid, respectively) separated by sports fields and facilities. The northern part has the Old and New Hulsterplas, two connected recreational bodies of water created between the nineteen-sixties and -eighties. The southern part has the Kerkenhoek area with the Grote Kerk (Great Church) from 1830, first built in 1660; the former town hall; and the small Palthebos wood, once the possession of the Palthe family of clergy and landowners.

Rural cores and former hamlets that form part of Nieuwleusen include Den Hulst to the north, De Meele to the northwest and the Ruitenveen to the southwest.

New housing has been under construction for years. Construction is underway in various locations, notably to the west (the 'Westerbouwlanden').

Public transportation to and from Nieuwleusen include bus routes 301 between Zwolle and Coevorden, 649 (a school bus) between Zwolle and Dedemsvaart and 217, all operated by Syntus Overijssel. Roads leading into Nieuwleusen include the N377 (from Hasselt), N758 (from Zwolle) and N757 (from Dalfsen).

Nieuwleusen came into existence in the first half of the seventeenth century. At the time, most of the area between Leusen, a village on the Vecht, and the Reest on the border with the province of Drenthe consisted of inaccessible peat moors. The entire area of the Vechtdal, from Hasselt to Coevorden, is indicated as 't Veen (the Peat Moor) on a map by Abraham Goos from the early seventeenth century. The area where Nieuwleusen now lies is called the Ommer moer (Moor of Ommen) on the same map.

On 8 January 1631, the Luessener Compagnie was established by inhabitants of Zwolle and Kampen to cultivate the area north of Leusen, which belonged to the Marke van Leusen (the local association of land owners). It was mainly pioneers from Leusen who made the land arable. The first farms of the new settlement stood along the Pad (Path), today the Oosterveen road. Hence, Nieuwleusen got its early name of Oosterveen, as seen on the earliest area maps. Once the settlement got its name of Nieuwleusen (New Leusen), the original Leusen got to be called Oudleusen or Old Leusen (Low Saxon: Oldlusen). It is believed that leusen in these names means lo-essen, approximately 'wooded fields' - which would have been descriptive of the (Old) Leusen area and carried over into the name of Nieuwleusen.