This Letter describes a model-independent search for the production of new resonances in photon + jet ( γ+jet ) events using 20 fb −1 of proton–proton LHC data recorded with the ATLAS detector at a centre-of-mass energy of s=8 TeV . The γ+jet mass distribution is compared to a background model fit from data; no significant deviation from the background-only hypothesis is found. Limits are set at 95% credibility level on generic Gaussian-shaped signals and two benchmark phenomena beyond the Standard Model: non-thermal quantum black holes and excited quarks. Non-thermal quantum black holes are excluded below masses of 4.6 TeV and excited quarks are excluded below masses of 3.5 TeV.