Fontenai-sur-Orne is a former commune in the Orne department of Lower Normandy, France. There were 254 people in 2006. The size of the village is 651 hectare (ha). Its Saint-Martin church was built in classical times. The west gate was built in 16th century, but the Virgin statues are from the 18th century. An underground vaulted cave made in stone is in the presbytery. There is a local party organized on the 3rd Sunday of July. The city's main activities are mixed farming and bird-raising. On 1 January 2018, it was merged into the commune Écouché-les-Vallées.