In this study, the effect of photodynamic therapy with topical corticosteroid in oral lichen planus patients was compared. In this randomized, double-blind clinical trial, eight patients with bilateral oral OLP lesions were recruited. Toluidine blue was applied on the lesions of both sides; a 660-nm diode laser InGaAlP was irradiated for 10min (power: 25mW, fluence: 19.23J/cm2 , probe cross section: 0.78cm2 ) for three sessions. In the control side of the oral mucosa, only sham laser was used. Follow-up sessions were held on weeks 3 and 7. In week 3, oral paste triamcinolone acetonide 0.1% was prescribed. Response rates were assessed clinically by VAS, Thongprasom sign scoring, clinical severity index, efficacy indices, and the amount of reduction in the size of the lesions. The Mann-Whitney test was used to evaluate the treatment outcomes. In spite of the control side, all scores improved significantly between sessions 0 and 4 for the intervention side. The differences between the changes in almost all scores between sessions 0 and 4 in both the intervention and control sides were significantly considerable (p value<.05). Photodynamic therapy can be used as an alternative therapy alongside standard methods or as a new modality for refractory OLP.