Flexible, stretchable RFID tags are formed by a pocket that is formed from one or more substrates and layers of adhesive, and an electronic circuit that is located within this pocket. The RFID tags can include a stretchable substrate and an electronic circuit attached to the stretchable substrate by one or a finite number of discrete spaced apart attachment locations. When the pocket is formed by relatively thick adhesive layers adhering together one or more flexible substrates to form an internal cavity, the electronic circuit is located within this cavity and either is not adhered to any of the substrates of the cavity, and is free to move about within the cavity, or the electronic circuit can be attached to a substrate by a thin layer of adhesive.