The aim of this study was to find an alternative to synthetic fungicides currently used in the control of postharvest fungal diseases of citrus. Antifungal activities of essential oils from fourThymusspecies were investigated againstPenicillium digitatum,Penicillium italicumandGeotrichum citri-aurantii.The essential oils, obtained by hydrodistillation from aerial parts of fourThymusspecies were submitted to gas chromatography hyphenated with mass spectrometry analysis. The main constituents were carvacrol (76.94%) forThymus leptobotrys, borneol (27.71%) and thymol (18.47%) forThymus satureioidessubsp.pseudomastichina, camphor (46.17%) and α-terpineol (7.69%) forThymus broussonnetiisubsp.hannonisand carvacrol (32.24%), γ-terpinene (19.60%) and p-cymene (13.52%) forThymus riatarum. In thein vitromycelial growth assay, complete inhibition of the three pathogens was obtained byT. leptobotrysandT. riatarumessential oils, at 1000 μl L−1. The effect of essential oils on spore germination varied significantly between testedThymusspecies.T. leptobotrysessential oil displayed the highest bioactivity, inhibiting completely the spore germination ofG. citri-aurantiiat 250 μl L−1and ofP. digitatumandP. italicumat 500 μl L−1.T. riatarumessential oil was able to inhibit completely the spore germination ofG. citri-aurantii(2000 μl L−1) and bothPenicilliumspecies used as target organisms (1000 μl L−1). The essential oil ofT. leptobotryshad the lowest minimum inhibitory concentration (MIC) for the three pathogens (MIC value < 500 μl L−1). These findings suggest that essential oils obtained fromT. leptobotrys,T. riatarumandT. satureioidessubsp.pseudomastichinamay be useful and effective agents for control of citrus fungal pathogens.