  We present here the first result on the three-loop gluon jet function in
perturbative QCD. Using the three-loop coefficient functions [1,2] for
deep-inelastic scattering via the exchange of a virtual photon that couples to
quarks or a scalar that couples to gluons and employing the KG equation,
renormalization group invariance and factorization theorem, we obtain both the
quark and the gluon jet functions up to the three-loop level. The former agrees
with the recent result [3]. These jet functions being universal ingredients for
many collider and decay processes, will play an important role in the
phenomenological studies at the Large Hadron Collider.
