Cuarny is a municipality in the district of Jura-Nord Vaudois of the canton of Vaud in Switzerland.
Cuarny is first mentioned in 1174 as Quarnie.
Cuarny has an area, , of . Of this area, or 67.6% is used for agricultural purposes, while or 25.8% is forested. Of the rest of the land, or 7.0% is settled (buildings or roads) and or 0.2% is unproductive land.
Of the built up area, housing and buildings made up 1.5% and transportation infrastructure made up 5.0%. Out of the forested land, all of the forested land area is covered with heavy forests. Of the agricultural land, 54.9% is used for growing crops and 9.8% is pastures, while 2.8% is used for orchards or vine crops.
The municipality was part of the Yverdon District until it was dissolved on 31 August 2006, and Cuarny became part of the new district of Jura-Nord Vaudois.
The municipality is located east of Yverdon. It consists of the linear village of Cuarny, the estate of Fignerolles and, since 1964, La Grand-Fin which came from the municipality of Pomy.
The municipalities of Cronay, Cuarny, Pomy, Ursins, Valeyres-sous-Ursins and Villars-Epeney are considering a merger on at a date in the future into the new municipality with an, , undetermined name.
The blazon of the municipal coat of arms is Argent, in base three Rayonnes Gules; in chief Gules three Owls Argent.
Cuarny has a population () of . , 5.4% of the population are resident foreign nationals. Over the last 10 years (1999–2009 ) the population has changed at a rate of 0.6%. It has changed at a rate of -1.7% due to migration and at a rate of 3.4% due to births and deaths.
Most of the population () speaks French (168 or 98.2%) as their first language, with Italian being second most common (2 or 1.2%) and German being third (1 or 0.6%).
The age distribution, , in Cuarny is; 19 children or 10.7% of the population are between 0 and 9 years old and 16 teenagers or 9.0% are between 10 and 19. Of the adult population, 25 people or 14.1% of the population are between 20 and 29 years old. 24 people or 13.