A fiber channel-interchangeable fiber optic connector includes an adapter, two connectors respectively rotatably mounted in respective axle holes at the front side of the adapter, a sub-assembly detachably attached to the adapter to stop the connectors from rotation and hold down the connectors in position, and a cable inserted through the sub-assembly and mounted in the adapter with two optical-fiber cores therein respectively inserted into ferrules of the connectors. Detaching the sub-assembly from the adapter allows rotation of the connectors and the sub-assembly through 180-degrees angle relative to the adapter to interchange the fiber channels.