Abstract: A tag threader apparatus includes a flat base and a spring-biased first class lever pivotally mounted on the bottom side of the base. A pad on one end of the lever may be depressed for pivoting the lever and reciprocating a string threading plunger, pivotally connected to the other end of the lever, through a guide on the bottom side of the base and a central portion of a string guiding groove in the base. The string to be inserted is received along the groove and is carried by an upper free end of the plunger through a hole in a tag positioned on the base. Overhanging ledge structures on the base guide and restrain the tag at a desired position on the base in which its hole is aligned with the plunger. Once the string has been pushed through the tag hole, it may be grasped as the tag is removed from the base.