Based on Weinberg’s work on Lorentz‐transformation properties of massless particles, we discuss the little group for photons and gauge transformations from a pedagogical standpoint. It is pointed out that the ’’translational’’ degrees of freedom associated with the photon little group can generate a transformation which guarantees the transversality of the four‐vector representation for photons. This little‐group transformation, which leaves the photon momemtum invariant, can be regarded as a gauge transformation.

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