The invention provides a tag identification system, a tag reading apparatus, and a method for determining sequence of tags. According to an aspect of the invention, a tag identification system comprises a tag reading apparatus and a plurality of tags, wherein: the tag reading apparatus has at least two antennas, wherein the apparatus transmits an interrogation signal within the coverage of each of the antennas; the plurality of tags sequentially pass by the coverage of each of the at least two antennas, each of the plurality of tags returning a reply to the at least two antennas in response to a received interrogation signal; and the tag reading apparatus includes a sequence determination unit which determines the sequence in which the plurality of tags pass by based on replies returned from the plurality of tags and received by the at least two antennas.