A search is reported for Higgs boson decay to μ⁺μ¯ using data with an integrated luminosity of 24.8 fb(-1) collected with the ATLAS detector in pp collisions at s=7and8 TeV TeV at the CERN Large Hadron Collider. The observed dimuon invariant mass distribution is consistent with the Standard Model background-only hypothesis in the 120–150 GeV search range. For a Higgs boson with a mass of 125.5 GeV, the observed (expected) upper limit at the 95% confidence level is 7.0 (7.2) times the Standard Model expectation. This corresponds to an upper limit on the branching ratio BR(H→μ+μ−) of 1.5×10−31.5×10−3.