The Wopmay orogen is a Paleoproterozoic orogenic belt in northern Canada which formed during the collision between the Hottah terrane (north of the Hottah Lake), a continental magmatic arc, and the Archean Slave Craton at about 1.88 Ga (billion years). The collision lead to the short-lived Calderian orogeny.
The formation was named for Wilfrid Reid "Wop" May, OBE, DFC (April 20, 1896 – June 21, 1952), a Canadian flying ace in the First World War and a leading post-war aviator.
It is approximately 500 km along the north–south axis, and 200 km along the east–west axis at its widest point, tapering at both the northern and southern ends.