In this study, the potential of Eucalyptus oils as green collectors in gold flotation was examined. Flotation tests were conducted on a sample of Boddington's copper-gold sulfide ores. Eucalyptus oil compositions were determined by gas chromatography-mass spectrometry. Gold association of flotation products was investigated by Mineral Liberation Analyzer. It was found that Eucalyptus oils have the potential to replace potassium amyl xanthate as a collector in free gold flotation. The collecting power of Eucalyptus oils is correlated to the percentage of non-polar and weakly polar constituents, and in particular 1,8-cineole, phellendrene and pipertone. Eucalyptus oils possess strong selectivity for free gold rather than gold carriers, and therefore achieve high gold grades at the head of the flotation circuit.