Cordulegaster diadema, commonly known as the Apache spiketail, is a species of dragonfly in the family Cordulegastridae.

The mature adult is usually 74-88 millimeters long.

[3] It ranges from southwestern United States to Mexico and Costa Rica.

The back of the head is yellow to brown with yellow to black hairs, though some have been reported with a black head with white hairs.

[3] The first proximal segment of the legs are yellow.