Self-locking bundling ties for engagement about electrical cables, pipes or the like comprises a flat, metallic strap and a metallic head separably attached thereto. In the preferred form, the head is crimped to a folded-over end of the metallic strap. The head comprises a generally tubular housing with a generally planar locking insert slidably received in the housing cavity. The housing and insert include cooperative latching structure for holding the insert fixed in at least two positions relative to the housing. In a first position, the insert has an opening for receipt of the unattached end of the strap therethrough. Upon movement of the insert interiorly of the housing cavity to a second locked position, the insert opening with a portion of the strap end therethrough is moved interiorly of the housing and the strap end is deformed into a reverse bend to thereby lock the strap in the bundling tie head.