Deadbolt locking devices for preventing a deadbolt from being unlocked from the outside are provided. The deadbolt locking devices may include a connecting assembly, for engaging a door knob to provide leverage to resist turning of the handle of the deadbolt, and a housing member for engaging the handle of the deadbolt when in a locked position. The deadbolt locking devices can accommodate various configurations of door hardware without sacrificing convenience of use and without sacrificing confidence in its correct placement. Various configurations of door hardware can include the position of the deadbolt knob in relation to the door knob, the angular position of the handle of the deadbolt when it is in the locked position, whether the door is hinged on the left or right side and whether the deadbolt knob turns clockwise or counter-clockwise to lock the door.