This relates to a key cover for covering the head of a key. In one embodiment, the key cover is formed in two pieces, a cover member and a plug. In a second embodiment, the cover member and plug are pivotally connected. The cover member is provided with a cavity for receiving the key head with the blade of the key passing through a slot in the underside of the cover member. A plug is then readily insertable into the top of a cavity in overlying relation to the key head disposed within the cavity of the cover member and locked in place with the cover member. The interlock between the plug and the cover member is one wherein the plug cannot be readily removed unless the cover, for all practical purposes, is locked in place on the key. This permits the key cover to be individually applied to a key without materially disassociating the key from its respective lock.