Montreuil-au-Houlme () is a commune in the Orne department in north-western France.
The commune is made up of the following collection of villages and hamlets, La Crestinière and Montreuil-au-Houlme.
Montreuil-au-Houlme along with another 65 communes is part of a 20,593 hectare, Natura 2000 conservation area, called the Haute vallée de l'Orne et affluents.
The commune has one river running through it, The Maire and 2 streams, the Noeve & the Gué d'Arnettes.