A security tag assembly structured to restrict unauthorized removal of merchandise from a designated area is presented. The security tag assembly comprises a base and a tag member removably connected to the merchandise being protected or monitored. A locking assembly is disposed within the base and is structured to be biased into a locking orientation relative to a connector pin of the tag member. A release assembly, also disposed within the base, is structured to facilitate the authorized release of the locking assembly upon contact with an externally applied detachment assembly. In particular the release assembly comprises first and second members disposed in a movable interlocked relation with one another, wherein the first member is structured to be rotationally disposed upon contact with the detachment assembly. The second member is structured for disposition into a displacing engagement with the locking assembly upon the rotational movement of the first member.