The beverage container cover is a disposable security cover that is placed over an open beverage container that contains a beverage. The beverage container cover is placed over the open beverage container for the purposes of: 1) protecting the contents contained within the open beverage container from being tampered with while the open beverage container is unattended; 2) provide a visual indication that indicates that an attempt was made to tamper with the contents contained within the beverage container. The beverage container cover comprises a shell and a locking mechanism. The shell is wrapped around the beverage container to prevent tampering with the contents of the beverage container. The locking mechanism is a permanent lock that once engaged cannot be disengaged. The beverage container cover is removed by removing a perforated tab that is formed within the shell of the beverage container cover.