The four-lepton (4 ℓ , ℓ=e,μ ) production cross section is measured in the mass range from 80 to 1000 GeV using 20.3 fb −1 of data in pp collisions at s=8 TeV collected with the ATLAS detector at the LHC. The 4 ℓ events are produced in the decays of resonant Z and Higgs bosons and the non-resonant ZZ continuum originating from qq¯ , gg , and qg initial states. A total of 476 signal candidate events are observed with a background expectation of 26.2±3.6 events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton