Observations suggest that γ-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. In this talk, recent work on the production of high energy neutrinos by GRB fireballs is reviewed. A significant fraction of GRB energy is expected to be converted to an accompanying burst of high energy neutrinos. Photomeson interactions produce a burst of ∼ 100 TeV neutrinos in coincidence with the GRB, and a burst of ∼ 10 18 eV neutrinos following the GRB on a time scale of 10 s. Inelastic p− n nuclear collisions result in the production of a burst of ∼ 10 GeV neutrinos in coincidence with the GRB. Planned 1 km 3 neutrino telescopes are expected to detect tens of 100 TeV neutrino events, and several 10 18 eV events, correlated with GRBs per year. A suitably densely spaced detector may allow the detection of several 10 GeV events per year. The detection of high-energy neutrino events correlated with GRBs will allow to constrain GRB progenitor models and to test the suggestion that GRBs accelerate protons to ∼ 10 20 eV. Moreover, such detection will allow to test for neutrino properties, e.g. flavor oscillations (for which upward moving τ's would be a unique signature) and coupling to gravity, with an accuracy many orders of magnitude better than is currently possible.