Introduction: We aimed to determine the effect of lavandula angustifolia essential oil (LEO) on IL-23 and brain-derived neurotrophic factor (BDNF) gene expressions in peripheral blood mononuclear cells (PBMCs) of relapse-remitting MS (RRMS) patients. Methods : LEO was prepared using the hydrodistilation method on the plants aerial parts. 8 female RRMS patients and 8 healthy sex and age matched controls were entered into this study. PBMC cells were separated using Ficoll method and were treated with a concentration of 225 µg/ml LEO which and then the mRNAs were used for determining the effects of LEO on IL-23 and BDNF gene expressions using Quantitative Real Time PCR technique. Moreover in order to determine the anti-inflammatory effects of LEO, we measured the gene expression of IL-6 and IL-23 in stimulated healthy PBMC cells treated with LEO. Results: Results showed that there is no significant difference between PBMC of patients compared to healthy controls in case of IL-23 gene expression. Moreover, LEO has no significant effect on gene expression of IL-23 in PBMC of neither patients nor control. Also the results showed that BDNF gene expression is reduced to 41% compared to healthy controls and LEO can increase the BDNF gene expression by 81% in patients PBMCs. Moreover we observed that LEO can significantly reduce the LPS stimulated IL-6 gene expression in healthy PBMCs but had no significant effect on IL-23 gene expression. Conclusion : The present study demonstrated that L.angustifolia essential oil may have a protective effect against neuron damage via increasing the gene expression of BDNF in PBMCs from RRMS patients. However, further studies are necessary to confirm our results.