Objectives: To evaluate the effectiveness of Photodynamic Therapy (PDT) in the treatment of Oral Potentially Malignant Disorders (OPMDs) patients. Methodology: An electronic search was conducted to retrieve articles published until September 2021. Meta-analyses were conducted for the outcomes of complete response (CR) and any response (AR) after treatment with PDT using data from single-arm studies, case series and non-randomised controlled trials (NRCTs). Results: In total, 49 articles were included. RCTs revealed insignificant mean difference (MD) in efficacy index between PDT and comparison groups (MD: 1.32; 95% CI:-28.10–30.72, p=0.930). The likelihood of CR (OR:0.84; 95% CI: 0.42–1.71, p=0.637) or AR (OR:2.10; 95% CI: 0.31–14.25, p=0.448) was not different in PDT group when compared with any comparison treatments in NRCTs. CR/AR among single arm studies was 60.6% (95% CI: 50.5–70.7, P<0.001) and 93.7% (95% CI:91.5–95.8, P<0.001) respectively. Higher prevalence of CR and AR was observed for dysplasia or carcinoma insitu (CIS) (CR: 81%, 95% CI: 70.8–91.3, P<0.001; AR: 94.3%; 95% CI: 89–99.6, P<0.001) and actinic cheilitis (AC) (CR: 73.9%, 95% CI: 65.9–81.9, P<0.001; AR:97%; 95% CI:94.9–99, P<0.001). Conclusions: More than half of the patients receiving PDT showed CR, with more than 90% responding to the treatment. PDT was most effective on oral dysplasias, followed by AC.