Salmonella enterica serotype Enteritidis and S. enterica serotype Typhimurium are frequently present among poultry and are associated with outbreaks of human salmonellosis. The study investigated the in vitro antimicrobial activity of essential oils (EOs) obtained from Aloysia triphylla, Cinnamomum zeylanicum, Cymbopogon citratus, Litsea cubeba, Mentha piperita, Syzygium aromaticum against S. Enteritidis and S. Thyphimurium strains previously isolated from poultry. A 1:1 mixture of C. zeylanicum and S. aromaticum was also tested. The activity of all compounds was evaluated against the yeast Saccharomyces cerevisiae, commonly used as probiotic. The highest antibacterial activity was observed for C. zeylanicum (minimum inhibitory concentrations (MICs) ranging from 1.26 mg/mL to 0.63 mg/mL), S. aromaticum (MICs from 2.637 mg/mL to 0.164 mg/mL) and the mixture (MICs from 1.289 mg/mL to 0.322 mg/mL). No activity was recorded against S. cerevisiae. The results suggest a possible use of C. zeylanicum and S. aromaticum, alone or in combination, in the farm environment for disinfection and in poultry diet, combined with S. cerevisiae administration, for an integrated approach to avoid Salmonella intestinal colonization.