Periodontitis is defined as "an inflammatory disease of the supporting tissues of the teeth caused by specific microorganisms or groups of microorganisms." Mechanical removal of the biofilm and adjunctive use of antibacterial disinfectants or various antibiotics have been conventional methods of periodontitis therapy. Photodynamic therapy (PDT) involves the use of low-power lasers with an appropriate wavelength to kill microorganisms treated with a photosensitizer drug. Hence, PDT could be an alternative to conventional periodontal therapeutic methods. This review aims to discuss the evolution and uses of photodynamic therapy.